The US military has been crowdsourcing ideas for “creative and unconventional” ways to “punish” Iran, according to a report, after both sides reached an impasse over how to end the unpopular five-month war.

A senior officer at the US Central Command’s intelligence branch is said to have written to military analysts last Wednesday asking for new ideas to “pressure and punish Iran”, according to CNN, citing two sources with knowledge of the matter.

Centcom spokesperson Captain Timothy Hawkins said: “US Central Command has a long history of thinking and working in innovative ways. [Centcom commander] Admiral [Brad] Cooper, in particular, reaches out to members of our great team, regardless of rank, to achieve the highest levels of operational performance possible.”

Military officials nonetheless told the outlet it was unusual to appeal for ideas like that by email. One of the sources told CNN that Centcom was reviewing all of its options, acknowledging the need to re-evaluate its current strategy.

The Trump administration has been pressuring Iran with strikes in recent weeks in a bid to shake its grip on the Strait of Hormuz and return to negotiations with leverage to discuss Iran’s nuclear programme.

President Donald Trump said over the weekend that he had called off a supposed “massive attack” on Iran following requests from Saudi Arabia, the UAE, Qatar and Iran. Iranian state media did not say they had urged Trump to hold back.

Trump added that negotiations with Iran would begin again on Monday, but Iran’s foreign ministry flatly denied the claims this morning, saying that they had no plans for such talks and would not be moved to reopen the strait so long as US “aggression” continues.

Last week, reports emerged suggesting that Trump was “exasperated” by the lack of progress in ending the Iran conflict and the lack of consensus on strategy among his top military advisers.

“There was not a real strategy for how long or what they should do to get to the endpoint… He did not intend this to be a long, drawn-out war,” an unnamed ally of the president told NBC News.

The US president met with Israeli prime minister Benjamin Netanyahu in Washington last week, with an Israeli official saying they had explored all possible paths to curb Iran's nuclear program, including diplomacy, economic pressure and force.

Asked on Sunday whether there was a deadline for Iran to come to an agreement, Trump declined to answer. He told reporters in response: “Would I rather make a deal? I'm not looking to kill people because people die, a lot of people die, and we don't want that.”

Trump has argued that his stated goal of keeping Iran from gaining nuclear weapons justifies higher fuel costs in the near term, but the economic pain has put political pressure on him to find a way to end the conflict.

The continued closure of the Strait of Hormuz has forced up global energy prices. Iran has also floated the idea of charging fees for future transit through the strait, although last month it publicly rejected an Omani proposal, backed by Gulf states, to manage the strait they neighbour. People familiar with the matter said the plan included the collection of voluntary fees for using the strait.