US senators have rejected a resolution curbing President Donald Trump’s power to wage war on Iran — their first vote on the conflict since a 60-day deadline expired for the White House to seek formal authorisation, AFP reports.

The measure, introduced by Oregon Senator Jeff Merkley, was the seventh failed attempt by Democrats to rein in Trump’s war powers since the conflict began more than 10 weeks ago.

Democrats say that, under the War Powers Act, the administration had until May 1 to secure congressional approval for military action after Trump notified lawmakers in early March of strikes against Iran.

The administration disputes that interpretation, arguing that the clock was paused by a ceasefire announced more than a month ago.