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.
As the BBC writes, Xi told Trump to be "careful" when supplying weapons to the island, adding that he "attaches great importance" to ties with Washington and hopes the two sides can find ways to resolve differences.
Trump described the call as "great" and "long and thorough."
Wednesday's call follows a series of visits by Western leaders, including Britain's Keir Starmer, to China in recent months, in the hope of restoring relations with the world's second-largest economy.
Trump himself is expected to visit China in April, a trip he says he is “very much looking forward to.” He added that Beijing is considering buying 20 million tons of soybeans from the United States, up from the current 12 million tons.
"The relationship with China, and my personal relationship with President Xi, is extremely good, and we both understand how important it is to keep it that way," he wrote in a post on Truth Social.
The two leaders last spoke in November on a range of issues, including trade, the Russian invasion of Ukraine, fentanyl and Taiwan, according to Trump and China's foreign ministry.
In addition to Taiwan and soybeans, Trump and Xi also discussed Russia's war in Ukraine, the current situation in Iran, and China's purchase of US oil and gas.
Regarding Taiwan, Xi said the self-ruled island was "China's territory" and that Beijing "must safeguard (Taiwan's) sovereignty and territorial integrity."
"The US should handle the issue of arms sales to Taiwan carefully," he warned, according to state-run Xinhua news agency.
China has long promised "reunification" with Taiwan and has not ruled out the use of force to achieve this.
The US has formal ties with Beijing but not with Taiwan, walking a tricky diplomatic tightrope for decades. But it remains a strong ally of Taiwan and the island's largest arms supplier.
In December, the Trump administration announced a major arms sale worth about $11 billion to Taiwan, which included advanced missile launchers and a range of missiles.
Beijing said at the time that this "attempt to support (Taiwan's) independence" would "accelerate the escalation towards a dangerous and violent situation in the Taiwan Strait."
"Just as the US has its own concerns, China on its side also has concerns," Xi told Trump on Wednesday.
“If both sides work in the same direction in the spirit of equality, respect and mutual benefit, we can certainly find ways to address each other's concerns,” he said.
Hours before the call with Trump, Xi held a virtual meeting with Russian leader Vladimir Putin, where both praised the strengthening of ties between Beijing and Moscow.