U.S. President Donald Trump says he will meet Chinese President Xi Jinping in China on 14-15 May, after delaying the landmark trip amid the US-Israel war with Iran.

This would be the first visit to China by a US president in nearly 10 years.

Trump is also set to host Xi in Washington D.C., later this year, and officials are "finalising preparations for these Historic Visits", he wrote on Truth Social on Wednesday.

White House press secretary Karoline Leavitt confirmed the dates of Trump's visit, telling reporters that President Xi had understood and accepted the request to postpone the trip.

"President Xi understood that it's very important for the president to be here throughout these combat ​operations right now," Leavitt said at a press briefing on Wednesday.

Beijing has not responded to the dates listed by Trump - though it does not typically reveal Xi's schedule so far in advance. China's foreign ministry said earlier this month that it was in talks with Washington over the timing of Trump's visit.

The trip, originally slated for 31 March, was delayed after the US and Israel launched wide-ranging strikes on Iran last month, killing the country's supreme leader.

In response, Iran attacked Israel and US-allied states in the Gulf and effectively closed the Strait of Hormuz - a key waterway for the world's oil and liquefied natural gas - leading to a global fuel crisis.

Trump has urged US allies to help unblock the strait. He also threatened Iran with attacks on its energy production infrastructure if it did not allow full access through the waterway.

When asked if the Iran war would wind down by the time Trump visits China, Leavitt said they had "always estimated approximately four to six weeks, so you can do the math on that".

The last time a US president visited China was in November 2017, during Trump's first term.

The last time Trump and Xi met was last November in South Korea, on the sidelines of the Apec summit.

Ties between the two countries have long been plagued by sore spots ranging from trade friction to tech competition and geopolitical tensions. Trump's visit will be closely watched for any signs of easing tensions.

Ahead of Trump's visit, Chinese state media has encouraged US officials to visit and interact with their Chinese counterparts.

A Global Times editorial published on Thursday said the lack of people-to-people exchanges between the countries and the long absence of a US presidential visit to China was "abnormal and should not be the case".

"History has repeatedly shown that both China and the US stand to gain from cooperation and lose from confrontation," it said.