Relations between the US and China have been warmer since Donald Trump and Xi Jinping met in April

Chinese President Xi Jinping told US counterpart Donald Trump on Monday that Sino-US relations have been hit by "negative factors" in a phone call following days of US actions that have vexed Beijing.

Trump held separate calls with Xi and Japanese Prime Minister Shinzo Abe that focused on tensions on the Korean peninsula, but China's foreign ministry said Xi also invoked the thorny issue of Taiwan.

A series of US moves and China's angry responses have marked a sharp reversal from the friendly tone struck by Trump since his meeting with Xi at the US president's Mar-a-Lago resort in Florida in April.

Trump infuriated Beijing last week when he approved a $1.3 billion arms sales to Taiwan, a self-governed island that Beijing considers a breakaway province awaiting reunification.

The US administration also imposed sanctions on a Chinese bank accused of laundering North Korean cash, voiced concern about freedom in semi-autonomous Hong Kong and placed the country on a list of the world's worst human trafficking offenders.

The latest irritant came on Sunday as Beijing lashed out at a "serious political and military provocation" after a US warship sailed close to an island claimed by China, Taiwan and Vietnam.

Map showing disputed claims in the South China Sea

It was the second US "freedom of navigation" patrol in the South China Sea since Trump took office in January, an operation meant to assert the right to sail in disputed waters.

China deployed three warships and two fighter jets to warn the US vessel to "move away", defence ministry spokesman Wu Qian said in a statement.

Wu called it an "unawful act" and warned that China will "strengthen the construction of various defence capabilities, intensify maritime and air patrols and firmly defend its sovereignty and security according to the degree of threats".

In the phone call with Trump, Xi acknowledged that Sino-US relations "have achieved important results" since their April meeting, the foreign ministry said.

But Xi also warned that relations "have been affected by some negative factors" and that he hoped the US president will "properly handle" Taiwan issues in accordance with the "One China" principle.

The Chinese leader, however, insisted that the two sides should follow the "consensus" reached at Mar-a-Lago and declared that the two presidents agreed to meet at the Group of 20 summit in Germany this week.

- N. Korea a 'growing threat' -

In its readout of the conversation, the White House said Trump raised "the growing threat posed by North Korea's nuclear and ballistic missile programmes".

The USS Stethem passed less than 12 nautical miles (22 kilometers) from the tiny Triton Island

"Both leaders reaffirmed their commitment to a denuclearised Korean Peninsula," the statement said.

Trump, who berated Beijing over trade during the US election campaign, also "reiterated his determination to seek more balanced trade relations with America's trading partners".

The US statement did not mention Taiwan or the freedom of navigation operation, but it said the two leaders discussed "a range of other regional and bilateral issues of mutual interest".

In their own phone call, Trump and Abe discussed their "unity with respect to increasing pressure on the (North Korean) regime to change its dangerous path", the White House said.

Trump has pressed Xi to use China's diplomatic and economic clout over North Korea to pressure the Stalinist state to abandon its nuclear programme, but the US leader tweeted last month that Beijing's efforts had failed.

Michael Cole, a Taipei-based academic with the University of Nottingham's China Policy Institute, said Trump appears to have realised, quicker than his predecessors, that Beijing would not help resolve the North Korean issue.

China may respond by temporarily suspending military-to-military relations, impose its own sanctions on US firms and further pressure Taiwan, he told AFP.

"The Trump administration has been trying to find its footing since entering the White House," he said, "and what we're going through at the moment are the pangs of a return to continuity."

But foreign ministry spokesman Geng Shuang told a press briefing that both countries were "determined to press ahead with our relationship" despite encountering "some issues".