US Defense Secretary Lloyd Austin spoke with Chinese Minister of National Defense General Wei Fenghe on Wednesday, the first call between the two officials since the start of President Joe Biden's administration more than a year ago.
Relations between China and the United States have been tense, with the world's two largest economies clashing over everything from Taiwan and China's human rights record to its military activity in the South China Sea.
Pentagon spokesman John Kirby said the two talked about relations between the countries and "regional security issues, and Russia's unprovoked invasion of Ukraine."
Despite the tensions and heated rhetoric, US military officials have long sought to have open lines of communication with their Chinese counterparts to be able to mitigate potential flare-ups or deal with any accidents.
Austin, despite multiple attempts, had been unable to talk with Chinese military leaders until Wednesday.
A US official, speaking on the condition anonymity, said the call, which lasted about 45 minutes, did not have any major breakthroughs but Austin reiterated the importance of Beijing not arming Russia for its invasion of Ukraine.
A statement from Beijing said that Wei told Austin that Taiwan was a part of China and no one could change that.
"If the Taiwan issue were not handled properly, it would have a damaging impact on Sino-US relations," Wei added, according to statement published by the defense ministry.
The United States has no formal relations with self-ruled Taiwan, which Beijing claims as its own, but is its most important international backer and arms supplier.
Taiwan has been heartened by the US support offered by the Biden administration, which has repeatedly talked of its "rock-solid" commitment to the democratically governed island.
Russia's invasion of Ukraine has also put Taipei on alert for any possible moves by Beijing to use the Ukraine crisis to make a move on the island. The government though has reported no sign that China is about to invade.