WASHINGTON: The United States plans high-level talks with "Quad" security partners from India, Australia and Japan in September and October, President Donald Trump's national security adviser said on Friday, while criticizing "very aggressive" behaviour by China.

Robert O'Brien told the Atlantic Council think tank he would likely meet his opposite numbers from those countries in Hawaii in October, while secretary of state Mike Pompeo would meet his counterparts from the so-called Quad in September and October.

O'Brien said the United States had an "amazing amount of stake" in the India-Pacific region.

"It's really the engine of the world economy going forward and America's gonna play a big role there. One of the ways that we can do that is providing for a safe and secure Indo-Pacific through our defence partnerships and our diplomatic partnerships with our allies," he said.

O'Brien said the Quad relationship, which has been denounced by China, was coming into its own and likely to pay huge dividends.

"We're seeing a very assertive, a very aggressive China and the United States is not going to back down from its long-held principles that the world's ocean ways and international waters should be free for navigation, and the same with space and with air rights and international airspace," he said.

US-China tension has risen in the run-up to the US election in November and the countries' military forces have stepped up activities in the Indo-Pacific region.

On Thursday, the Pentagon expressed concern about China's recent military exercises, including the firing of medium-range ballistic missiles in the South China Sea.

China criticized a U.S. warship operation near the Paracel Islands, which China claims, along with most of the sea.

The Quad engagement was revived in 2017 to deepen security cooperation and coordinate alternatives for regional infrastructure financing offered by China.