Trump on Tuesday indefinitely extended a two-week truce with Iran to allow more time for negotiations, while maintaining a U.S. blockade on Iranian ports.

Tehran has yet to formally respond to the extension.“The current regional situation stands at a critical juncture transitioning between war and peace; the paramount priority remains to make every effort to prevent a resumption of hostilities,” Chinese foreign ministry spokesman Guo Jiakun told a regular press briefing.

Guo did not directly address the specifics of the ceasefire extension but said Beijing would continue to play a “constructive” role in promoting stability in the region.

China has consistently called for de-escalation amid rising tensions linked to the conflict involving the United States and Iran, emphasizing diplomatic engagement and the protection of regional security.

Donald Trump said on Sunday that U.S. forces would start blockading maritime traffic to Iranian ports, escalating tensions after negotiations failed to produce an agreement to end the conflict, putting a fragile two-week ceasefire at risk.

US Central Command said the blockade would take effect at 10 a.m. ET (1400 GMT) and would apply to all vessels entering or leaving Iranian ports across the Arabian Gulf and the Gulf of Oman. It added that freedom of navigation through Hormuz to non-Iranian destinations would not be impeded.

Shipping data showed several vessels adjusting routes in response. The Malta-flagged very large crude carrier Agios Fanourios I reversed course after attempting to enter the Gulf and is now anchored near the Gulf of Oman.

Other tankers, including the Pakistan-flagged Shalamar and Khairpur, continued operations, heading toward the United Arab Emirates and Kuwait respectively to load cargo.

The Liberia-flagged VLCC Mombasa B also transited the strait earlier on Sunday and is currently ballasting in the Gulf, according to vessel tracking data.Iran’s Islamic Revolutionary Guard Corps warned that any military vessels approaching the strait would be considered a violation of the ceasefire and would face a “decisive” response.

Despite rising tensions, shipping data showed that three fully laden supertankers passed through the strait on Saturday, appearing to be among the first vessels to exit the Gulf since the ceasefire agreement was reached last week.

Speaking to reporters aboard Air Force One, Trump said Washington would not oppose a shipment from Russia or other countries if intended to alleviate shortages. “If a country wants to send some oil into Cuba right now, I have no problem whether it’s Russia or not,” he said.

Shipping data cited in reports shows a tanker carrying roughly 730,000 barrels of oil nearing Cuba’s eastern coast, with an expected arrival in Matanzas. The vessel is expected to deliver fuel that could yield about 180,000 barrels of diesel, enough to meet the country’s demand for more than a week.

The tanker, identified as the Anatoly Kolodkin, is under sanctions imposed by the United States, the European Union and the United Kingdom following the war in Ukraine.

Trump’s remarks come despite his administration’s intensified efforts to restrict oil flows to Cuba in a bid to pressure its government. He has previously threatened punitive tariffs on third countries supplying oil to the island.

The blockade has contributed to widespread fuel shortages, with reports of prolonged blackouts and disruptions to public transport and healthcare services across Cuba.Cuba has long been a focal point of strategic competition between the United States and Russia.

Trump dismissed suggestions that allowing the shipment would benefit Russian President Vladimir Putin, saying the delivery would have limited impact beyond addressing immediate needs.

He said he would prefer allowing fuel deliveries to ease hardship for civilians, citing the need for electricity, heating and cooling as essential services.