BEIJING - China firmly opposes US legislation on Taiwan's bid to join the International Civil Aviation Organization (ICAO), a spokeswoman for China's Foreign Ministry said on Tuesday.

Spokeswoman Hua Chunying said Taiwan's participation in international organizations, including the ICAO, is part of the internal affairs among the Chinese and the Chinese side opposes the interference of any foreign government, organization or individual.

On Friday, US President Barack Obama signed the bill, which passed both chambers of the US Congress in June, to endorse Taiwan's campaign to join the ICAO as an observer member. Media reports say an ICAO assembly in September is expected to vote on Taiwan's status.

The US bill has "seriously violated" the one-China policy as well as the three China-US joint communiques, and the Chinese side has lodged solemn representations to the US side, Hua said.

"We urge the US side to strictly fulfill its commitment to the Chinese side on Taiwan-related issues, handle those issues in a cautious and appropriate way, and stop interfering in China's internal affairs," she said.

"(The US side) should do more things that are conducive to the peaceful development of the relationship between the two sides across the (Taiwan) Strait, not the other way around," she added.