Secretary of Commerce Wilbur Ross testifies during the House Oversight and Government Reform Committee hearing on the census on Thursday, Oct. 12, 2017.

The United States has downgraded its participation in back-to-back Asia-Pacific summits in Bangkok next week, a move bound to disappoint Asian partners worried by China's expanding influence.

While President Donald Trump is expected to attend the Asia Pacific Economic Cooperation forum in Chile in mid-November, the most senior official from his administration who will be in Bangkok next week when Thailand hosts the annual East Asian Summit and U.S.-ASEAN Summit will be Commerce Secretary Wilbur Ross, the White House said in a statement.

Ross is scheduled to lead the U.S. delegation to an Indo-Pacific Business Forum grouping government officials and business executives on the sidelines of the EAS.

Trump, a Republican, has named White House national security adviser Robert O'Brien as his special envoy to the summits, the White House said.

David Stilwell, the State Department's assistant secretary for East Asia and the Pacific, will also be in Bangkok, but the U.S. delegation will be significantly outranked by other regional players including, Japan, India and China.

Despite declaring Indo-Pacific "the single most consequential region for America's future" in a Pentagon strategy report this year, the Trump administration has steadily scaled back U.S. presence at the EAS and ASEAN gatherings.

While Trump attended the U.S.-ASEAN summit in Manila in 2017, he has never attended a full EAS meeting. Vice President Mike Pence represented the United States at the meetings in Singapore last year.

Trump's predecessor, Democrat Barack Obama, by contrast attended every U.S.-ASEAN and East Asia summit from 2011, apart from 2013, when he canceled due to a government shutdown at home.

Asian diplomats say the lack of top-level U.S. representation in Bangkok will be a significant if not unexpected disappointment in a region increasingly concerned about China's fast-expanding influence.

Trump plans to attend the primarily economics-focused meeting of APEC in Chile, where he has said he hopes to sign the first part of a deal with China to resolve a prolonged and damaging trade war.

However, diplomats and analysts say Trump's absence in Bangkok will raise questions about U.S. commitment to the region, especially after his withdrawal from the 11-nation Trans Pacific Partnership trade agreement in 2017, shortly after he took office.

Last year, Trump, who is currently embroiled in a congressional impeachment inquiry, sent Pence in his place to attend APEC as well as the ASEAN and the East Asia summits.

Matthew Goodman, senior adviser for Asian economics at Washington's Center for Strategic and International Studies think tank, called U.S. attendance plans for Bangkok "a real issue."

"As Woody Allen said, either 80 or 85 percent of life is showing up. And in the Indo-Pacific, that's definitely true," he told a news briefing previewing the summits. "If you show up, you're given praise, whatever you actually say or do. If you don't show up, it's a real problem."

Amy Searight, who was a senior defense official under Obama and is now a senior adviser at CSIS, said the EAS summit had become the premier strategic dialogue forum for the Asia Pacific, drawing leaders from China, India, Japan and South Korea, as well as those of the 10 ASEAN, or Association of Southeast Asian Nations, states.

"It'll be headlines in the region that no senior American leader is coming to a summit with 17 other leaders from the Indo-Pacific," she said.

"And I think it really does call into question ... how serious this administration is in its Free and Open Indo-Pacific strategy," she said. "And it really just calls into question the reliability of the United States as a strategic partner to this region."