(CNN) A US nuclear powered submarine struck an object underwater in the South China Sea on Saturday, according to two defense officials.
A number of sailors on board the USS Connecticut were injured in the accident, the officials said. None of the injuries were life-threatening, according to a statement from US Pacific Fleet. It's unclear what the Seawolf-class submarine may have hit while it was submerged.
"The submarine remains in a safe and stable condition. USS Connecticut's nuclear propulsion plant and spaces were not affected and remain fully operational," the statement said. "The incident will be investigated." The US Navy did not specify the incident took place in the South China Sea, only that it occurred in international waters in the Indo-Pacific region.
The accident happened as tensions between the US and China soared over the Chinese military's incursions into Taiwan's Air Defense Identification Zone (ADIZ).
The Connecticut was operating in the waters around the South China Sea as the US and its allies have been carrying out a major multinational show of force in the region led by the United Kingdom's Carrier Strike Group 21. The ongoing operations saw exercises with ships from the US, UK, Japan, Australia, Canada, and the Netherlands, including three aircraft carriers, training in and around the South China Sea.
On Saturday, 39 Chinese military aircraft, including fighter jets and transport aircraft, entered Taiwan's ADIZ, causing the Taiwanese air force to scramble jets and deploy air defense missiles to monitor the aircraft. Two days later, China sent 56 aircraft into Taiwan's ADIZ within 24 hours, the highest number since the self-governed island began publicly releasing such numbers last year.
"We are very concerned by the PRC's provocative military activity near Taiwan," US Secretary of State Tony Blinken told reporters at a news conference in Paris Wednesday when asked about the Chinese activity. "As we said, the activity is destabilizing. It risks miscalculation and it has the potential to undermine regional peace and stability. So, we strongly urge Beijing to cease its military, diplomatic and economic pressure and coercion directed at Taiwan."
On Wednesday, Taiwan's defense minister, Chiu Kuo-cheng, said China could be ready to launch a "full-scale" invasion of the island by 2025, adding that "they currently have the ability" to attack, but they would have to "pay a price."
The Biden administration has shifted the focus of US national security policy away from the wars of the past two decades and towards Beijing, which has asserted itself in the region and on the world stage. On Thursday, the Central Intelligence Agency announced the creation of a new mission center for China following a months-long review that found China as the greatest long-term threat to the United States.
One day earlier, national security adviser Jake Sullivan met a high-ranking Chinese official in Switzerland in what one senior administration official called a "candid, direct, and wide-ranging discussion."
The meeting, which the official said had a "different tone" than an acrimonious meeting between Sullivan and his Chinese counterpart six months ago, set the stage for a virtual meeting between President Joe Biden and Chinese President Xi Jinping later this year in an effort to ensure stability.
But the agreement in-principle between the two leaders to meet did little to alleviate the current friction in the region, nor did it ease the friction around the South China Sea, where China has built a series of bases on reefs and artificial islands in the disputed waterway.
In response to a report in the Wall Street Journal on the presence of US troops in Taiwan, the Pentagon highlighted its support for Taiwan and its defense needs.
"Our support for and defense relationship with Taiwan remains aligned against the current threat posed by the People's Republic of China," said Pentagon spokesman John Supple on Thursday, accusing China of actions that are "destabilizing and increase the risk of miscalculation."
As relations between the US and China soured, the State Department requested in June 2018 that US Marines be sent to Taiwan help safeguard the de facto US embassy there. At the time, there were only 10 US troops in the Taiwan, according to Defense Department workforce records, and only one was from the Marine Corps, which is the branch of the military in charge of embassy security. The number gradually increased to 19 troops two years later, before jumping to 32 troops earlier this year, the records show. Similarly, the number of US troops in China increased from 14 in 2018 to 55 now, the majority of which are Marines.
"The US defense relationship with Taiwan is guided by the Taiwan Relations Act and based on an assessment of Taiwan's defense needs and the threat posed by the PRC, as has been the case for more than 40 years," Supple said.
The comments are part of a series of escalating rhetorical attacks between the two superpowers engaged in what Pentagon officials call "Great Power Competition."
Earlier this week, China criticized the US for what it called "irresponsible remarks," after the US condemned the Chinese military flights in Taiwan's ADIZ. "In recent times, the United States has continued its negative actions in selling weapons to Taiwan and boosting its official military ties between the United States and Taiwan," said the spokeswoman of China's Foreign Ministry, Hua Chunying.
CORRECTION: This story has been updated with the correct name for Taiwan's Air Defense Identification Zone and to clarify that the United Kingdom's Carrier Strike Group 21 is leading a show of force in the region.