The East Asia visit on Tuesday, Pompeo's first in more than a year, coincides with worsening tensions with China. Yet the call for a united front against Beijing is a sensitive subject for Washington's allies, which are reliant on China for trade.

In comments before the start of a meeting of the Quad grouping of the four nations' foreign ministers, Pompeo spoke in typically unsparing terms against Beijing's ruling Chinese Communist Party.

That was in contrast to his three counterparts, all of whom avoided calling out China directly.

"As partners in this Quad, it is more critical now than ever that we collaborate to protect our people and partners from the CCP's exploitation, corruption and coercion," Pompeo said, referring to the ruling party.

"We see it in the South and East China Seas, the Mekong, the Himalayas, the Taiwan Strait."

China has denounced the Quad as an attempt to contain its development.

Pompeo's visit was supposed to include trips to Mongolia and South Korea but was cut back to one day after President Donald Trump was diagnosed with COVID-19.

He also reiterated the Trump administration's criticism of China's handling of COVID-19 after it first broke out in the city of Wuhan.

"When we met, now, last year, the landscape was very different. We couldn't have imagined a pandemic that came from Wuhan. That crisis was made infinitely worse by the Chinese Communist Party's cover-up," he said.

"The regime's authoritarian nature led its leaders to lock up and silence the very brave Chinese citizens who were raising the alarm."

The Quad meeting is unlikely to yield a specific action plan, although the gathering itself may serve as a warning to China and play to its fears that the grouping might one day grow into a formalised structure like NATO, experts have said.

The United States and China, the world's top two economies, are at loggerheads over a wide range of issues from Beijing's handling of the coronavirus to its imposition of a new security law in Hong Kong and ambitions in the South China Sea.

Most Asian allies have been pleased with Washington's toughness toward their regional rival China but have not so eagerly welcomed Trump and Pompeo's highly charged recent rhetoric and remain wary of going too far in antagonising China.

Part of the problem for Washington's Asian allies is their dependence on China for trade. China was the top destination for Australian exports in 2019, the No.2 destination for Japanese exports and the No.3 destination for Indian exports, according to IMF direction of trade statistics compiled by Refinitiv.

Japanese Foreign Minister Toshimitsu Motegi said after the talks the nations had confirmed they would advance with practical talks on infrastructure, cybersecurity and other areas.

Australian Foreign Minister Marise Payne said the Quad promotes an inclusive, open Indo Pacific, a common refrain among the ministers.

The United States has said it greatly values the meeting of the Quad grouping of foreign ministers as a platform to strengthen its solidarity against China with regional allies.

"We're hoping to have some significant announcements, significant achievements," Pompeo had told reporters in the United States before departing for Tokyo, declining to say what they would be.

As expected, there was no joint statement from the members.

Australian Associated Press