The US and China have agreed to resume military-to-military communications in an effort to ease rising tensions, President Joe Biden says.
"We're back to direct, open, clear communications," he said following a rare meeting with China's President Xi Jinping in California on Wednesday.
It was the first time the pair had spoken in person in more than a year.
But there were still signs of tension between the two - Mr Biden repeated his view that Mr Xi is a dictator.
China's foreign ministry later criticised the remarks, but they do not appear to have taken the shine off what both sides are portraying as a largely successful meeting.
Mr Biden also said both leaders had agreed to establish a direct line of communication with one another.
At a news conference following the summit, which took place at a historic country estate near San Francisco, Mr Biden said a lack of communication was "how accidents happen" and added that both presidents could now "pick up the phone and be directly heard immediately".
China severed military-to-military communications last year after then-US House Speaker Nancy Pelosi visited Taiwan. Beijing views self-ruled Taiwan as its territory, and has threatened to annex it by force if necessary.
Mr Biden said that, while many disagreements remained between the pair, Mr Xi had "just been straight". He said the talks were "some of the most constructive and productive discussions we've had".
Speaking later at a dinner with US business leaders, Mr Xi spoke openly about wanting to pursue better relations with the US.
He said he and President Biden agreed to continue on a path of diplomacy and co-operation.
"The door of China-US relations cannot be closed again now that's open," he said. "We need to build more bridges and pave more roads between each other."
But in a sign of how difficult relations still are, Mr Biden, as he was exiting the stage, responded to a reporter's question by saying he considered Mr Xi a dictator.
"He's a dictator in the sense that he is a guy who runs a country... based on a form of government that is totally different from ours," he said. When Mr Biden made a similar comment in June, Chinese officials reacted angrily and described it as "extremely absurd and irresponsible".
On Thursday, China's foreign ministry condemned Mr Biden's remark, saying the description was "extremely wrong" and "irresponsible political manipulation".
It was a sour note in what is seen as an overall positive meeting between the two leaders.
The "dictator" remark was noticeably absent in state news agency Xinhua's readout of the meeting. The readout - which can sometimes be an indication of how good or bad the Chinese government perceives relations to be - featured talk of substantial progress in bilateral ties.
As well as resuming military communications, the two sides announced several other agreements in areas that have become sources of tension in recent times.
These included taking steps to tackle the flow of fentanyl into the US, which has contributed to a rise in overdose deaths in the country.
Chinese manufacturing companies are a source not only of the synthetic opioid itself but of precursor chemicals which can be combined to make it. "We're taking action to significantly reduce the flow of precursor chemicals and pill presses from China to the Western Hemisphere," Mr Biden said.
Under the deal, China will directly target companies that are producing those precursor chemicals. "It will save lives," Mr Biden told reporters.
The two leaders also discussed the conflict in Israel and Gaza. One senior US official told reporters that Mr Biden had asked China to use its influence with Iran to urge it not to take steps that could be seen as provocative.
The two superpowers further agreed to jointly examine artificial intelligence (AI), and had a lengthy conversation about Taiwan which, according to one US official, Mr Xi said was "the biggest, most dangerous issue in US-China ties".
Following the talks, China said communications were restored between the two militaries on "the basis of equality and respect".
While the meeting on the sidelines of the Asia-Pacific Economic Co-operation (Apec) summit had been highly anticipated, officials on both sides played down expectations of any major breakthroughs.
"The goals here really are about managing the competition, preventing the downside of risk - of conflict, and ensuring channels of communication are open," a senior US administration official said.
Relations deteriorated in February when a suspected Chinese spy balloon was shot down over US airspace.
US Secretary of State Antony Blinken visited Beijing in June, making him the highest-ranking Washington official to visit the Chinese capital in almost half a decade. He met President Xi and then foreign minister Qin Gang.
At the end of his trip, Mr Blinken said that while there were still major issues between the two countries, he hoped they would have "better communications [and] better engagement going forward".
