China's leader Xi Jinping called Taiwan the most important issue in China-US relations during a phone call with US President Donald Trump on Wednesday.
Xi had told Trump to be prudent when supplying weapons to the island, state media reported, adding that he attaches great importance to ties with Washington and hoped both sides will find ways to resolve their differences.
Trump cast the call as excellent and long and thorough.
Wednesday's call follows a flurry of visits by Western leaders, including UK's Keir Starmer, to China in recent months, hoping to reset relations with the world's second-largest economy.
Trump himself is due to visit China in April, a trip he says he very much looks forward to.
He added that Beijing is considering buying 20 million tonnes of US soybeans, up from the current 12 million tonnes.
The relationship with China, and my personal relationship with President Xi, is an extremely good one, and we both realize how important it is to keep it that way, he wrote in a Truth Social post.
The two leaders last spoke over the phone in November about a range of issues including trade, Russia's invasion of Ukraine, fentanyl and Taiwan, according to Trump and China's foreign ministry.
Apart from Taiwan and soybeans, Trump and Xi also discussed Russia's war in Ukraine, the current situation in Iran, and China's purchase of oil and gas from the US in the call on Wednesday, the US president wrote.
On Taiwan, Xi said the self-governed island was China's territory and that Beijing must safeguard [Taiwan's] sovereignty and territorial integrity.
The United States must handle the issue of arms sales to Taiwan with prudence, he warned, according to the state's Xinhua news agency.
China has long vowed to reunify with Taiwan and has not ruled out the use of force to do so.
The US has formal ties with Beijing rather than Taiwan, and has walked a tight diplomatic rope for decades. But it remains a powerful ally of Taiwan's and is the island's biggest arms supplier.
In December, the Trump administration announced a huge arms sale worth around $11bn (£8.2bn) to Taiwan, which included advanced rocket launchers, self-propelled howitzers and a variety of missiles.
Beijing said at the time that this attempt to support [Taiwan's] independence would only accelerate the push towards a dangerous and violent situation across the Taiwan Strait.
Just as the United States has its concerns, China for its part also has concerns, Xi told Trump on Wednesday.
If the two sides work in the same direction in the spirit of equality, respect and mutual benefit, we can surely find ways to address each other's concerns, he said.
Hours before his call with Trump, Xi held a virtual meeting with Russia's leader Vladimir Putin, in which both hailed the strengthening of ties between Beijing and Moscow.
