(CNN) Nothing is simple about the crisis in Syria.
With conflicting interests and competing global powers, the international community remains at an impasse over Syria's six-year conflict.
On Friday morning local time, the US military struck a Syrian air base in response to a chemical weapons attack, bringing mixed reaction from global players. Some lauded the action as long overdue, while others condemned it as "an aggression."
Here's a look at the key countries involved in Syria, their reactions to the strike and their stakes in the conflict.
Involvement: Since 2014, the United States has headed an international coalition conducting strikes on ISIS targets in Syria. Under former President Barack Obama's administration, the US launched a military campaign against ISIS in both Iraq and Syria. Since then, President Donald Trump's administration continued Obama's bombing campaign against ISIS.
But the strikes marked the first direct military action the United States has taken against the regime of Syrian President Bashar al-Assad.
Desired outcome: The Obama administration had said Assad must go. There are questions whether the Trump administration's approach to Syria will shift from his predecessor. A week ago, US Secretary of State Rex Tillerson said the "longer-term status of President Assad will be decided by the Syrian people." It remains to be seen how the strikes affect the Trump administration's policy on Syria.
Reaction: Opposes strike
Russian President Vladimir Putin regards the US attacks on Syria as "an aggression against a sovereign state in violation of the norms of international law, and under a trumped-up pretext at that," Kremlin spokesman Dmitry Peskov was quoted as saying by Russian state-run news agency Sputnik.
This could bring new strain in the US-Russia relationship.
"Cooperation between the Russian and US militaries may be shut down after the US strike," said Viktor Ozerov, head of the defense committee in the Federation Council to Russian state news agency RIA.
He said Russia will demand an urgent UN Security Council meeting after the US strike, calling it "an act of aggression against a UN member."
Involvement: Russia is Syria's most powerful ally and has provided the military might behind President Bashar al-Assad's grip on the country. Russia has significant economic and military interests in the country, such as a Mediterranean naval base at Tartus, that it is determined to keep. Throughout the years, it has staunchly shielded Syria from UN resolutions in the UN Security Council.
Desired outcome: Putin has made it clear that as far as he's concerned, Assad isn't going anywhere for the time being. More broadly, some analysts see Putin using Syria as an opportunity to send a message that it's a force to be reckoned with -- one the United States and its allies can't ignore.
Reaction: Supports strike
The Saudi Foreign Ministry expressed its "full support ... for the American military operations on military targets in Syria," according to a statement from the Saudi Press Agency.
An official source in the foreign ministry "noted the courageous decision of US President Donald Trump, which represents a response to crimes this regime has committed towards its people in light of the inaction of the international community in stopping it in its tracks."
Involvement: Saudi Arabia is one of the main supporters of insurgent groups battling the Syrian regime and ISIS. It is also one of the nations participating in the US-led coalition's strikes.
Desired outcome: Riyadh has pushed for Assad's ouster, and is not likely to settle for much less.
Reaction: Supports strike
Government spokesman Mohammad Momani said Jordan considers the strike "a necessary and appropriate response to the nonstop targeting of innocent civilians" with weapons of mass destruction.
Jordan reiterated its rejection and condemnation of the use of weapons of mass destruction, including the recent chemical attack against civilians in Khan Sheikhoun in Syria's Idlib province.
Momani called the chemical attack in Idlib province an "inhumane and heinous act." He repeated Jordan's support for all international efforts geared toward preventing future recurrence of using chemical weapons after Syria was declared free of them in the past.
Involvement: Jordan is part of the coalition fighting the Islamic State and has taken in hundreds of thousands of Syrian refugees. That influx has changed the makeup of the oil-less nation, which shares a 233-mile border with Syria.
Desired outcome: Jordan's King Abdullah II, speaking at a news conference with President Donald Trump in Washington on Wednesday, said, "We need a political solution that ends the conflict in the country and preserves its unity and territorial integrity. "
Reaction: Supports strike
''We welcome the US operation," said Turkish Foreign Minister Mevlut Cavusogulu.
Turkey called the strikes "a positive response to the Assad regime's war crimes."
Ibrahim Kalin, Turkey's presidential spokesman, said in a statement: "The destruction of Shayrat air base marks an important step to ensure that chemical and conventional attacks against the civilian population do not go unpunished." He also called for a no-fly zone and the creation of safe zones in Syria.
Turkish President Recep Tayyip Erdogan had called Assad a "murderer" over the chemical weapons attack on a rebel-held town in Syria's Idlib province.
Involvement: The country has a long, porous border with Syria. Thousands of foreign fighters have flowed over it into Syria and hundreds of thousands of refugees have poured out the other way.
Bitterly opposed to Assad, the Turkish government has long supported Syrian rebels. The rise of ISIS and other Islamic extremist groups has seriously complicated matters for Erdogan, who permitted the US-led coalition to launch bombing raids against ISIS positions from Turkish territory.
Desired outcome: Turkey wants to get rid of Assad, remove the growing threat of ISIS and end years of destabilizing conflict along its southern border. But it also wants to stop the Kurds from carving their own state out of the current chaos.
Reaction: Opposes strike
Iran "strongly condemns" the military strike, said Iranian Foreign Ministry spokesman Bahram Qasemi in the country's semi-official news agency ISNA.
"We strongly condemn any unilateral military action and the missile attack on the Al Shayrat air base in Syria by the US Navy and believe that such actions, which use the excuse of a suspicious chemical attack in Khan Sheikhoun in Idlib, whose timing and perpetrators are shrouded in a cloud of doubt, only strengthens terrorists who were already weak and adds to the complexity in Syria and the region."
Involvement: Tehran is a staunch backer of the Assad regime, funneling money, guns and fighters its way. Iran is in an alliance with Russia in its support of the Assad government. Iran's intervention in Syria is about a much bigger struggle against Sunni militancy.
Desired outcome: Iran, a majority Shiite nation, doesn't want a Sunni-dominated Syria -- especially as the rebels' main supporters are Iran's Persian Gulf rivals: Qatar and Saudi Arabia. Iran opposes a military solution to the Syrian conflict and supports one through a political process.
Reaction: Opposes strike
China's Foreign Ministry spokeswoman, when addressing questions on the US strikes on Syria, said the country opposes the use of force in international affairs, but also reiterated its stance opposing the use of chemical weapons.
"China always opposes the use of force in international affairs and we advocate resolving disputes peacefully through dialogues. ... We always hold that the Syrian issue should be resolved through political means."
China's "Global Times," a state-sanctioned tabloid, published an editorial saying that in Trump's "first major decision on international affairs, his haste and inconsistency has left people with a deep impression."
Involvement: China's relationship with Syria is more nuanced. Like Russia, China has repeatedly blocked sanctions attempts against the Syrian regime -- leading to a perpetual stalemate at the UN body to take any serious action on Syria. It's also a trading partner with Syria. There's a bigger factor though: China opposes foreign intervention in Syria.
Desired outcome: China's position is that foreign countries shouldn't meddle in Syria's internal affairs, and perhaps for good reason. China has had its own share of international controversies over its policies with Tibet as well as allegations of human rights violations.
Australia: Prime Minister Malcolm Turnbull said Australia "strongly supports the swift and just response of the US" to the chemical attack in Idlib province.
Syria "committed a shocking war crime" and the US response was "calibrated, proportionate, and targeted," which will "send a strong message to the Assad regime."
Israel: The Prime Minister of Israel's account tweeted that "Israel fully supports President Trump's decision."
"In both word and action, @POTUS sent a strong and clear message today that the use and spread of chemical weapons will not be tolerated.
Japan: "The Japanese government supports the US government's resolve that it will never tolerate the spread and use of chemical weapons," Japanese Prime Minister Shinzo Abe told reporters.
United Kingdom: "The UK government fully supports the US action, which we believe was an appropriate response to the barbaric chemical weapons attack launched by the Syrian regime, and is intended to deter further attacks," a UK government spokesperson said in a statement.
Spain: "The Spanish government considers that the action taken by the United States in recent hours against a military base in Syria is a measured and proportionate response to the use of chemical weapons against the civil population of the country by the Syrian army," according to a Spanish government statement.
Italy: "Italy understands the reasons for a US military action, proportionate and well-timed, as a response to an unacceptable feeling of impunity, and as a deterrence signal against the risk of further use of chemical weapons by Assad," Italian Foreign Minister Angelino Alfano said in a statement on Friday.
North Korea: A North Korean government official who spoke on condition of anonymity told CNN International Correspondent Will Ripley in Pyongyang that "the US missile attack upon Syria is a clear act of aggression upon a sovereign state which can never be tolerable. We denounce these strikes in the strongest possible terms."
North Korea also provided Ripley with a lengthy comment from "relevant government departments" in response to a question from CNN about the US missile strikes on Syria.
"In some quarters, they say these military attacks are a warning shot against the DPRK (North Korea), but we are not at all frightened by those actions. The Syrian crisis is a bloody lesson which has been deeply engraved into the bones of the Korean people, the lesson being that we should never harbor any illusions about imperialists. And the lesson being that one can defend oneself from imperialist acts of aggression with only one's own strength."
European Council President Donald Tusk: "US strikes show needed resolve against barbaric chemical attacks. EU will work with the US to end brutality in Syria," he said in a tweet.
German Chancellor Angela Merkel: "This attack by the United States of America is understandable, given the aspect of the war crimes, given the suffering of innocent people and given the logjam in the UN Security Council."
French President François Hollande, in a joint statement with Merkel, said the two European leaders were given prior notice of the US operation. "Assad is entirely responsible for the development of the situation. His constant use of chemical weapons and his massive crimes must not go unpunished," the joint statement reads.
NATO Secretary General Jens Stoltenberg: "The Syrian regime bears the full responsibility for this development. NATO has consistently condemned Syria's continued use of chemical weapons as a clear breach of international norms and agreements."