(CNN) The United States is lifting decades-old restrictions between American and Taiwanese officials, in a move that will fundamentally change Washington's relationship with the self-governed island -- prompting threats from Beijing.
Washington has for years "created complex internal restrictions to regulate" US officials' dealings with Taiwan "in an attempt to appease the Communist regime in Beijing," US Secretary of State Mike Pompeo said in a statement on Saturday. "No more," Pompeo wrote.
China considers Taiwan a part of its territory, and US dealings with the democratically ruled island have long been a source of tension.
In a statement, Pompeo, a staunch critic of China, wrote that US diplomats should now consider all previous State Department contact guidelines regarding relations with Taiwan to be "null and void."
The order comes less than two weeks before the administration of President-elect Joe Biden takes over, and is likely to be a hurdle for the incoming team to deal with.
The US has maintained close ties with Taiwan since it split from mainland China in 1949 after the end of a bloody civil war. But until recently Washington has avoided major displays of friendship so as to not antagonize Beijing, which continues to view the self-governing democracy of around 24 million people as an inseparable part of its territory, under its One China policy.
China's leader, President Xi Jinping, has been clear in his ambitions to "reunify" the island with the mainland, and has refused to rule out the use of force, even though the ruling Chinese Communist Party has never exerted direct control over Taiwan.
Under the One China policy, the US has unofficial relations with Taiwan and posts unofficial representatives to Taipei. Washington has also long provided arms to the island under the terms of the 40-year-old Taiwan Relations Act.
On Monday, China's Ministry of Foreign Affairs spokesman Zhao Lijian warned Beijing would "resolutely hit back" in response to the US announcement.
"China firmly opposes the above-mentioned actions by the US and strongly condemns them," said Zhao Monday. "The so-called US law on relations with Taiwan seriously violates the one-China principle and the provisions of the Three Joint Communiques," Zhao added.
"We will never allow anyone or any force to block China's reunification process and use the Taiwan issue to interfere in China's internal affairs. Any act that harms China's core interests will be resolutely hit back by China and won't be successful," said Zhao.
Tensions between China and the US over Taiwan have worsened in recent months, as top Trump administration officials have visited the self-governed island. Beijing has escalated pressure on Taiwan through a series of military drills and aircraft incursions.
In September, Keith Krach, the Under Secretary of State for Economic Growth, Energy, and the Environment, visited Taiwan, a month after Secretary of Health and Human Services Alex Azar made a trip, ostensibly to discuss coronavirus prevention measures but also in a highly symbolic show of support by the Trump administration for Taipei.
At the time, China's Ministry of Foreign Affairs spokesman Wang Wenbin said the US and Taiwan must "immediately stop" official exchanges. "China firmly opposes any form of official exchanges between the United States and Taiwan. This position is consistent and clear," Wang said.
Now Pompeo has cleared US diplomats and other government officials to deal with their Taiwan counterparts just like they would counterparts from any other country.
"The United States government maintains relationships with unofficial partners around the world, and Taiwan is no exception. Our two democracies share common values of individual freedom, the rule of law, and a respect for human dignity. Today's statement recognizes that the US-Taiwan relationship need not, and should not, be shackled by self-imposed restrictions of our permanent bureaucracy," Pompeo wrote.
The US Ambassador to the United Nations, Kelly Craft, is set to visit Taiwan this week to "reinforce the US government's strong and ongoing support for Taiwan's international space," Pompeo announced last week.