Trading has been volatile this week after the president's weekend outburst against Beijing and announcement of more tariffs on $550 billion of goods was followed Monday by him saying the two sides had spoken by phone and negotiations would resume soon.

However, China has not confirmed such calls had taken place, while media in the country has played down the chances of more talks and the leadership's need for a deal.

The developments are the latest in a series of moves by the White House that have seen it slam China and then hold out an olive branch.

But Stephen Innes at Valour Markets said: "There remains a high degree of scepticism regarding the sincerity of Trump's comments or even if the Chinese are willing to recommence negotiations."

He pointed out that an inflammatory tweet on Friday in which Trump labelled Federal Reserve boss Jerome Powell and China's Xi Jinping enemies of the US had resonated among traders.

"Risk-off remains in vogue as trade disputes continue to flare, suggesting any risk assets recovery will remain extremely fragile."

The editor of the state-run Global Times said in a tweet that Beijing was "not putting so much emphasis on trade talks", instead focusing on boosting the economy, and it was becoming tougher for the US to apply pressure.

- 'Large grain of salt' -

"A four-word disclaimer, 'large grain of salt', on any presidential pronouncements would probably do wonders for reducing the whipsaw volatility of the last week," said Jeffrey Halley, senior market analyst at OANDA.

Worries about the outlook continue to dim, with the yield on two-year Treasury notes rising above those for 10-year notes, which is a widely accepted sign a recession is likely.

In share trading Hong Kong and Sydney each edged up 0.1 percent, Tokyo ended the morning 0.2 percent higher and Seoul was 0.6 percent. Singapore was flat, Taipei added 0.5 percent and Wellington jumped 0.9 percent.

Manila and Jakarta were up but Shanghai fell 0.4 percent.

China's yuan edged up slightly after a recent sharp sell-off but it remains lodged around 11-year lows.

Oil prices built on Tuesday's surge that came in response to figures showing US stockpiles dived more than 11 million barrels last week, lifting hopes for demand and offsetting worries about the impact of the trade war.

Also providing support was Iranian President Hassan Rouhani's call for the United States to lifting all sanctions against before he would meet Trump, after the US leader had said he would be open to talks.

The Islamic republic's foreign minister said the chances of a face-to-face were "unimaginable", meaning there was little chance of a thawing of tensions that would see the return of Iranian oil onto markets.