Chinese President Xi Jinping told Saudi Arabia’s Crown Prince Mohammed bin Salman that “normal navigation” through the Strait of Hormuz “should be maintained,” state media reported Monday, as tensions escalate over the key global shipping route.

“Normal navigation through the Strait of Hormuz should be maintained, this is in the shared interests of regional countries and the international community,” Xi said during a phone call, according to state broadcaster CCTV.

Xi also stressed that China “advocates for an immediate and comprehensive ceasefire,” positioning Beijing as a stabilizing force amid the ongoing conflict involving the United States, Israel and Iran.

China is a major trading partner of Gulf countries and the largest buyer of Iranian oil, most of which transits through the Strait of Hormuz.

The remarks came as uncertainty deepened over efforts to resume negotiations between Washington and Tehran. Iran said it has no plans to attend a new round of talks with the United States.

Donald Trump said he was sending negotiators to Pakistan to seek an end to the conflict, while again warning of possible strikes on Iran’s energy infrastructure if no deal is reached.

Tensions have intensified following accusations from both sides of ceasefire violations. The United States seized an Iranian cargo ship early Monday, which Trump said was attempting to evade a blockade on Iranian ports.

Iran said the U.S. actions breached a two-week truce set to expire overnight Tuesday and warned it could retaliate. Trump, meanwhile, accused Tehran of violating the ceasefire in the Strait of Hormuz, which has been largely closed.

The competing claims have cast doubt over efforts to end the war that began with U.S.-Israeli strikes on Iran on February 28, which killed Iran’s supreme leader Ali Khamenei.