The top American diplomat made a flying visit to Beijing to brief China's leadership on Tuesday's historic meeting between US President Donald Trump and North Korean leader Kim Jong Un.

Pompeo appeared with Wang in Beijing's Great Hall of the People for a brief press conference, where the two discussed the prospects for cooperation on ending Pyongyang's nuclear weapons programme.

But while the two world powers have worked together to pressure Pyongyang, their relations have becomes faced increasing tensions on other issues.

One particular sore spot has been the massive trade imbalances between the two countries, a bone of contention for Trump.

"Our deficit with China is still too high," Pompeo warned, adding the issue was a key concern for the US president, who will decide Friday whether to impose tariffs on billions of dollars of Chinese imports.

"We hope the US will meet the Chinese half way and use a win-win, instead of lose-lose approach," Wang said, imploring Washington to refrain from "creating further obstacles to our cooperation".

The two sides also aired grievances over security issues, with Wang saying he had "expressed grave concerns" over recent US actions on Taiwan, which China sees as a breakaway province.

Beijing has consistently opposed moves by the Trump administration to strengthen ties with the self-ruled island, which split from the mainland in 1949.

Two days after the US opened a de facto embassy in Taipei, Wang said he had urged the US to "stop official exchanges and all military links with Taiwan".

For his part, Pompeo said he had "reaffirmed our concern with respect to China's efforts to build and militarise outposts in the South China Sea, endangering the free flow of trade, and threatening the sovereignty of other nations and undermining regional stability".

Beijing has transformed reefs and islets in the resource-rich region's waters into artificial islands capable of hosting military facilities.

China had pledged it would not militarise the area, where it has overlapping claims with Vietnam and the Philippines, among others.

But the US has accused Beijing of breaking that promise by deploying a range of military hardware including anti-ship missiles, surface-to-air missiles and electronic jammers across the region.

Following his meeting with Wang, Pompeo met with Chinese President Xi Jinping, before heading back to Washington.