FILE PHOTO: Flags of U.S. and China are placed for a meeting at the Ministry of Agriculture in Beijing, China, June 30, 2017. REUTERS/Jason Lee/File Photo

SHANGHAI (Reuters) - China has postponed upcoming security talks with the United States at the request of Washington, a Chinese foreign ministry spokeswoman said on Tuesday, amid rising tensions between the two sides over trade, Taiwan and the South China Sea.

Spokeswoman Hua Chunying said in a statement posted on the website of the Ministry of Foreign Affairs that the two sides had initially agreed “in principle” to hold the second round of security talks in October.

“The United States has recently expressed its wish to postpone the dialogue,” she said, adding that the two sides would continue to “maintain communication” on the talks. She did not elaborate.

The meeting of the U.S. China Diplomatic and Security Dialogue, which first took place in Washington last year, was due to be held with U.S. Secretary of State Mike Pompeo and Secretary of Defense Jim Mattis.

A U.S. official confirmed on Sunday that the meeting had been canceled, though he did not say whether it was related to an escalating trade dispute, concerns about U.S. arms sales to self-ruled Taiwan, which Beijing claims as its own, or Chinese military activity in the South China Sea.

Sources in Beijing said last week that China’s People’s Liberation Army was unhappy with U.S. sanctions on the Chinese military and its approval of a new round of arms sales to Taiwan.