BEIJING (REUTERS) - Chinese President Xi Jinping told his US counterpart Joe Biden on Friday (March 18) that the Taiwan issue needs to be handled properly to avoid a negative impact on Sino-US relations, according to Chinese media reports.

China says Taiwan, which it views as a breakaway province to be brought back to the fold, by force if necessary, is the most sensitive and important issue in its relations with the United States.

Washington, which is seeking Beijing's help in restoring peace in Ukraine after Russia's Feb 24 invasion, has no formal diplomatic ties with Taipei but is Taiwan's most important international backer and arms supplier.

"Some individuals in the United States are sending the wrong signals to pro-independence forces in Taiwan, and that's very dangerous," Mr Xi told Mr Biden on a video call.

"If the Taiwan issue is not handled properly, it will have a subversive impact on the relationship between the two countries."

China sailed its aircraft carrier Shandong through the Taiwan Strait on Friday, shadowed by a US destroyer, a source with direct knowledge of the matter told Reuters, just hours before the Chinese and US presidents were due to talk.

A White House statement said Mr Biden reiterated in the call with Mr Xi that US policy on Taiwan has not changed, and emphasised that Washington "continues to oppose any unilateral changes to the status quo".

China has over the past two years stepped up its military activity near the island to assert its sovereignty claims.

China hopes the US side "will pay adequate attention" to the issue, Mr Xi told Mr Biden.

Taiwan's Foreign Ministry expressed thanks to Mr Biden for his "emphasis on maintaining the status quo of peace and stability across the Taiwan Strait, as well as his firm support for Taiwan's security".

It called on China to take concrete actions and condemn Russia's invasion of Ukraine. Taiwan, which rejects China's sovereignty claims, has joined in Western-led sanctions against Russia and sent humanitarian aid for Ukrainian refugees.

Mr Xi also told Mr Biden that the war in Ukraine must end as soon as possible, according to Chinese state media.

All parties should jointly support the Russia-Ukraine dialogue, while the United States and Nato should also conduct talks with Russia to solve the "crux" of the Ukraine crisis, Mr Xi said.