A U.S.-Iran ceasefire that began in early April has "terminated" hostilities between the two sides for the purposes of an approaching congressional war powers deadline, a senior official in President Donald Trump's administration said on Thursday.

Trump faced a deadline on Friday to end the Iran war or make the case to Congress for extending it, but the date was most likely to pass without altering the course of ​the war.

"For War Powers Resolution purposes, the hostilities that began on Saturday, February ​28, have terminated," said the official, describing the administration's thinking.

There has been no ⁠exchange of fire between the U.S. armed forces and Iran since a fragile ceasefire ​began more than three weeks ago, the official added.

Earlier, analysts and congressional aides had said they ​expected Trump to notify Congress that he planned a 30-day extension or to disregard the deadline, with the administration arguing the ceasefire marked an end to the conflict.

The 1973 law allows the president 60 days to wage military ​action before ending it, seeking authorization from Congress or asking for a 30-day extension on ​grounds of "unavoidable military necessity" for the safety of the armed forces.

The Iran war began with airstrikes launched by Israel ‌and the ⁠United States on February 28. Trump formally notified Congress of the conflict 48 hours later, triggering a 60-day deadline of May 1.

Defense Secretary Pete Hegseth told a Senate hearing on Thursday he understood that the 60-day clock stopped during the truce. Opposition Democrats disputed that, saying ​there was no such ​legal provision.

The U.S. Constitution ⁠says only Congress, not the president, can declare war, but the curb does not apply for operations the administration casts as short-term or ​countering an immediate threat.

Trump's Republican Party holds a narrow majority in ​both chambers of ⁠Congress. Democrats have tried since the war began to pass resolutions to force Trump to withdraw U.S. forces or obtain congressional authorisation.

Republicans have voted them down.

Iran responded to the February 28 attacks ⁠by ​the U.S. and Israel with its own strikes on Israel ​and Gulf states that host American bases. U.S.-Israeli strikes on Iran and Israeli attacks in Lebanon have killed thousands and displaced ​millions.