The U.S. military is preparing for the possibility of sustained operations lasting weeks against Iran if President Donald Trump orders a strike, two U.S. officials told Reuters.

The officials cautioned that such action could jeopardise ongoing diplomatic efforts between Washington and Tehran.

U.S. and Iranian diplomats held talks in Oman last week in an attempt to revive diplomacy over Iran’s nuclear programme, after Trump bolstered U.S. military forces in the region, raising concerns about the risk of renewed conflict.

U.S. officials said on Friday that the Pentagon would send an additional aircraft carrier to the Middle East, along with thousands of troops, fighter jets, guided-missile destroyers and other firepower capable of conducting or defending against strikes.

There was no immediate comment from the White House or the Pentagon on how imminent any military decision might be.