Trump last week threatened to "immediately" jack up tariffs should Xi fail to show at the meeting.

US President Donald Trump said Tuesday he had a positive phone conversation with his Chinese counterpart Xi Jinping and the two leaders will hold an "extended meeting" next week at the Group of 20 summit in Japan.

Trump's tweet set a more upbeat tone for his talks with Xi after worsening tensions creates fears over whether the world's top two economies would be able to resolve their differences and end an increasingly damaging trade war.

"Had a very good telephone conversation with President Xi of China. We will be having an extended meeting next week at the G-20 in Japan," Trump said on Twitter.

"Our respective teams will begin talks prior to our meeting."

The tweet came shortly before top US negotiator, Trade Representative Robert Lighthizer began his appearance before a Senate committee to discuss the status of the trade confrontation, as well as the new free trade agreement with Canada and Mexico.

Trump's tweet sparked a rally on Wall Street, where the multi-front trade battles have repeatedly rankled investors worried about dented corporate profits and disruption to one of the major axes of global trade.

Global markets are concerned about Trump's threat to impose more steep tariffs on China, to cover an additional $300 billion in goods, which could hurt the already slowing Chinese economy and spread the gloom worldwide.

Trump last week threatened to "immediately" jack up tariffs should Xi fail to show at the meeting. The US already has 25 percent duties on more than $250 billion of imports from China.

In addition to trade, Xi and Trump are expected to discuss US-led efforts to persuade North Korea to give up its nuclear arsenal.

Ahead of the G20 leaders' summit in Osaka, Japan, Xi will make the first visit to North Korea by a Chinese president in 14 years.