U.S. President Donald Trump said Saturday he will review a new Iranian peace proposal, but cast doubt over its prospects as he left open the possibility of future attacks on Iran.

Negotiations between the two countries have been deadlocked since a ceasefire came into effect on April 8, with one round of peace talks to end the more than two-month war having failed in Pakistan.

Iran said Saturday that it was up to the United States whether to pursue a negotiated settlement or to return to open war, but that Tehran was ready for either outcome.

A senior Iranian military officer said on Saturday that renewed fighting between the U.S. and Iran was "likely", hours after President Donald Trump said he was "not satisfied" with a new Iranian negotiating proposal.

U.S. President Donald Trump said on Friday the U.S. Navy was acting "like pirates" as he described an operation seizing a ship amid the tit-for-tat American blockade of Iranian ports.

"We... land on top of it and we took over the ship. We took over the cargo, took over the oil. It's a very profitable business," Trump said at a rally in Florida.

U.S. President Donald Trump said Friday that he was "not satisfied" with a new Iranian negotiating proposal, with peace talks between the two sides frozen despite a weeks-long ceasefire.

Iran has delivered a new proposal for talks with the United States via mediator Pakistan, state media reported on Friday.

Tehran's air defenses were activated to counter small aircraft and drones late Thursday, as the White House signalled that it will not be reined in by a congressional deadline on the Iran war.

The UK's terrorism threat level was raised Thursday to "severe", the second highest in the five-tier system, following an antisemitic terror attack the previous day in London, the interior ministry said.

Iran's President Masoud Pezeshkian on Thursday said a U.S. naval blockade of Iranian ports would deepen disruptions in the Gulf and fail to achieve its objectives.

Iran's supreme leader Ayatollah Mojtaba Khamenei said in a written message on Thursday that the United States had been defeated in its war with the Islamic republic, as the Iranian leadership defied President Donald Trump's warnings of a prolonged blockade.