President Donald Trump has sharply escalated his rhetoric against Iran, warning over the weekend that Tehran has little time left to improve its position at the negotiating table before the United States widens a military campaign now in its fourth month.

“For Iran, the Clock is Ticking, and they better get moving, FAST, or there won’t be anything left of them,” Mr Trump wrote in a social-media post on Sunday, after meeting senior members of his national security team. He is expected to gather the same advisers again early this week to weigh his options.

In a separate telephone interview, the president said that if the Iranian government did not put forward a better offer, “they are going to get hit much harder.” The remarks were his bluntest since a fragile ceasefire with Tehran began to fray earlier this month.

The Pentagon has prepared a menu of military options for Mr Trump to consider, according to officials, including targeted strikes on Iranian energy and infrastructure sites. The president has not said publicly whether, or when, he intends to act on them.

Mr Trump’s frustration has been driven in large part by the continued closure of the Strait of Hormuz, the narrow waterway through which a significant share of the world’s seaborne oil passes. The blockade has kept crude prices elevated and rattled financial markets for weeks.

The warning came days after the president returned from a summit in China, where he said he had secured a commitment from President Xi Jinping that Beijing would not provide material support to Iran. US officials have described that assurance as a central aim of the trip.

Diplomacy has not stopped entirely. Mediators from Egypt, Pakistan and Turkey have circulated a draft proposal for a 45-day ceasefire paired with the reopening of the Strait of Hormuz, with Islamabad acting as the principal channel between Tehran and Washington.

The conflict, which has drawn in a US and Israeli air campaign and a naval blockade, has already spilled well beyond Iran’s borders. A drone strike ignited a fire at the Barakah nuclear plant in the United Arab Emirates on Sunday, and prosecutors in several countries have linked recent plots against Jewish sites to Iran-backed groups.

For now, the administration’s posture is one of deliberate ambiguity. Mr Trump has left open both the prospect of a negotiated pause and the threat of a far heavier bombardment, leaving allies and adversaries alike to guess which way he will move.