By Chayut Setboonsarng, Liangping Gao and Trevor Hunnicutt
BANGKOK/BEIJING/WASHINGTON (Reuters) -Top Chinese and U.S. officials held candid talks in Bangkok aimed at lowering tensions between the superpowers on Taiwan and other subjects, ahead of an expected springtime call between President Joe Biden and Chinese leader Xi Jinping.
U.S. National Security Advisor Jake Sullivan pressed Chinese Foreign Minister Wang Yi to use his country's diplomatic influence to convince Iran to curtail support for Houthis attacking Red Sea merchant vessels, according to a senior Biden administration official.
The meetings, which spanned more than 12 hours over two days and wrapped on Saturday, are intended to deliver on Biden and Xi's agreement at a California summit in November to restore ruptured diplomatic talks on a range of global security and economic issues like defense and counter-narcotics despite significant disagreements.
China's foreign ministry and the White House said in statements that the two sides had agreed to keep in contact to manage sensitive issues.
Taiwan's defense ministry said on Saturday it detected 11 Chinese military planes crossing the Taiwan Strait's median line in the past 24 hours. The day before, the ministry reported 23 Chinese air force planes operating around Taiwan, carrying out "combat readiness patrols" with Chinese warships.
China claims the island as its own territory and has never renounced the use of force to bring it under its control. Taiwan strongly objects to China's sovereignty claims and says only the island's people can decide their future.
The United States switched diplomatic recognition from Taipei to Beijing in 1979 and has long said it does not support a formal declaration of independence by Taiwan. It does, however, maintain unofficial relations with the self-governed island and remains its most important backer and arms supplier.
Washington worries Beijing will use the election earlier this month of new Taiwan President Lai Ching-te as a pretext to test the U.S.'s support for Taiwan.
Lai, the current vice president from Taiwan's ruling Democratic Progressive Party (DPP), will take office on May 20. China has denounced Lai as a separatist and rejected his offers of talks. Lai has said repeatedly he does not want to change Taiwan's status.
Biden previously upset the Chinese government with comments that appeared to suggest the U.S. would defend the island if it were attacked. That stance deviates from Washington's long-held position of "strategic ambiguity."
Wang was quoted by the foreign ministry as saying Taiwan was China's internal affair, and a recent election there "cannot change the basic fact that Taiwan is a part of China."
China criticized the United States on Thursday for causing "trouble and provocation" after the U.S. Navy sailed its first warship through waters separating China and Taiwan since the election.
"The biggest risk to peace and stability in the Taiwan Strait is 'Taiwan independence' and the biggest challenge to China-U.S. relations is also 'Taiwan independence,'" Wang was quoted as saying.
LOWER THE TEMPERATURE?
Saturday's meeting was the fourth and latest quiet engagement between Wang and Sullivan, the two having met previously away from media to try to lower the temperature.
It sets the stage for an expected call between Xi and Biden in the coming months, potentially this spring, a senior Biden administration official said. That would be the eighth call or meeting between the leaders of Biden's presidency.
U.S. Secretary of State Antony Blinken is expected to travel to Beijing in the coming months, more military-to-military talks are planned in the coming months and counter-narcotics talks start between the countries on Tuesday in Beijing.
The U.S. is already seeing fewer seizures of illicit chemicals used to make fentanyl at U.S. airports after China moved to shut down companies that make them, the official said. The opioid is a leading cause of drug overdoses in the United States.
Biden, a Democrat seeking re-election in November, has worked to keep lines of communication open with Xi, seeing direct talks as the best way of influencing China's approach. Biden's likely opponent, Republican Donald Trump, has called for revoking China's most-favored-nation trading status.
Open conflict between the two countries in a U.S. presidential election year would strain the U.S. economy and stretch Biden's national security team, already dealing with a grinding Ukraine-Russia war, the Red Sea attacks and a Israel-Gaza conflict that has divided Biden's voter base.
China's struggling economy may dampen Beijing's appetite for a more combative relationship with Washington.
Wang and Sullivan also discussed North Korea, Myanmar and the South China Sea disputes between Beijing and countries including the Philippines, according to the U.S. official, agreeing to lower-level talks on some of those issues.
"Sullivan raised the importance of Beijing using its substantial leverage with Iran to bring an end to these dangerous attacks," in the Red Sea, the person said.
Reuters reported on Friday that Chinese officials have asked their Iranian counterparts to help rein in attacks on ships in the Red Sea by Yemen's Houthi group. The United States has previously asked China to make such overtures with Iran, the report said, citing Iranian and other sources.
"This is not the first time we have called on Beijing to play a constructive role," the U.S. official said, confirming that aspect of the Reuters report.
"We are certainly going to wait and see the results before we comment further on how effective we think - or whether we think they are actually raising it."
(Reporting by Chayut Setboonsarng in Bangkok, Liangping Gao in Beijing, and Trevor Hunnicutt in Washington; Additional reporting by Steve Holland and David Shepardson in Washington; Writing by Martin Petty; Editing by Nick Macfie, Diane Craft and Andrea Ricci)