TAIPEI, Sept 9 (Reuters) - A U.S. and a Canadian warship sailed through the Taiwan Strait on Saturday, the U.S. Navy said, marking the second such joint mission since June and coinciding with the leaders of both countries attending the G20 summit in India.

The U.S. Navy's 7th Fleet said the guided-missile destroyer USS Ralph Johnson and Canada's HMCS Ottawa conducted a "routine" transit "through waters where high-seas freedoms of navigation and overflight apply in accordance with international law".

"Ralph Johnson and Ottawa's bilateral transit through the Taiwan Strait demonstrates the commitment of the United States and our allies and partners to a free and open Indo-Pacific," the U.S. Navy added in a statement.

China's military condemned the transit as is usual with such missions, accusing the ships of carrying out "public hyping" in the strait, which separates Chinese-claimed Taiwan from China.

Taiwan's government strongly rejects China's sovereignty claims, saying only the island's people can decide their future.

The Eastern Theatre Command of China's People's Liberation Army said its forces monitored the ships and "handled" the situation in accordance with the law and regulations.

Taiwan's defence ministry said the ships sailed in a southerly direction and that it had observed nothing unusual.

The mission was announced by the U.S. Navy as the G20 summit in New Delhi was wrapping up, skipped by Chinese President Xi Jinping but attended by both U.S. President Joe Biden and Canadian Prime Minister Justin Trudeau.

After the June joint sailing, the U.S. Navy released a video of what it called an "unsafe interaction" in the Taiwan Strait, in which a Chinese warship crossed in front of a U.S. destroyer.

While U.S. warships transit the strait around once a month, it is unusual for them to do so with those of other allies.

China has been increasing its military operations around Taiwan over the past few years in response to what it calls "collusion" between Taiwan independence forces and the U.S.