RAYONG, Feb 28 (Reuters) - Thailand and the United States kicked off on Tuesday military exercises involving more than 7,000 personnel and forces from 30 countries, with the annual drills including a component focused on space exercises for the first time.

"Cobra Gold", launched in 1982, is one of the world's longest-running multilateral military exercises and the biggest in Southeast Asia, serving as a key platform for Washington to shore up alliances in Asia at a time of increasing competition with China.

After the drills were scaled back during the pandemic, nearly 6,000 U.S. troops will take part this year, Admiral John Aquilino, Commander of the United States Indo-Pacific Command, said, the highest number in a decade.

Speaking to reporters, Aquilino said: "we will conduct integrated ops across the land, sea, air and cyberspace with our partners."

The exercises, which will run until March 10, demonstrate how responding together would help "to preserve a free and open Indo Pacific, so that all nations can maintain peace, stability and prosperity," he said.

Tensions have increased in the region between the United States and China over Beijing's growing assertiveness in the South China Sea and over self-ruled Taiwan.

This year, the drills will include a space exercise for the first time, with a focus on understanding the impact of aerial phenomena such as solar storms on military operations, communication and satellites, a U.S. embassy statement said.

Military and civilian space agencies from Thailand, the United States and Japan will take part, it said.

Cobra Gold involves 7,394 personnel in total this year from 30 countries, with the seven full participants also including Japan, Singapore, South Korea, Malaysia and Indonesia.

China, India and Australia are taking part in the humanitarian exercises.