The Chinese foreign ministry has yet to confirm whether the pair will discuss the conflict in the Middle East, which Islamabad and Beijing have both sought to mediate in.

US President Donald Trump has described the stop-start negotiations with Iran as teetering on the "borderline" between renewed attacks and a deal to end the war, which began with US-Israeli strikes on Iran in February and has engulfed the Middle East and roiled the global economy.

Sharif "arrived in Hangzhou, Zhejiang province, on Saturday to begin a four-day official visit to China," state news agency Xinhua said, without elaborating.

Earlier in the week, Chinese foreign ministry spokesman Guo Jiakun said only that "issues of common concern" would be discussed.

Guo has said that China would work with Pakistan to "make positive contributions to the early restoration of peace and stability in the Middle East".

"China supports Pakistan in playing a fair and balanced mediating role in promoting peace and ending the war," he said.

Pakistan has emerged as a central mediator between the United States and Iran, hosting historic face-to-face talks last month that failed to yield a lasting agreement.

Its army chief Field Marshal Asim Munir was due in Tehran on Thursday, Iranian media reported.

China has played a quieter role, shepherding phone calls and meetings with officials of affected Gulf countries.

After high-profile talks with Chinese President Xi Jinping in Beijing last week, Trump told Fox News the Chinese leader had offered Beijing's help to reopen the Strait of Hormuz -- a key oil route largely blocked since the war erupted.

China's Foreign Minister Wang Yi urged Islamabad this month to "step up mediation efforts" in the Middle East, speaking to his Pakistani counterpart Ishaq Dar in a call.

In the past two weeks, Bejing has hosted visits from Trump and Russian President Vladimir Putin.