The latest developments follow US and Israeli strikes on Iran that began on Saturday, triggering Iranian counterattacks targeting Gulf states and Israel.
The rapidly escalating hostilities have raised fears of a wider regional conflict.
The intensifying violence has also severely disrupted air travel.
Several countries across the Middle East have shut their airspace amid security concerns.
According to aviation analytics firm Cirium, at least 12,903 flights were cancelled between Saturday and Monday, roughly 40 percent of all scheduled services during that period.
Meanwhile, in a shift from his earlier hardline posture, US President Donald Trump said “boots on the ground” may not be necessary following the attack on the US embassy in Riyadh, Saudi Arabia, media reports said.
Speaking to NewsNation, Trump said, “We’re doing a lot of damage. We’re inflicting tremendous damage on them,” without elaborating on immediate next steps.
Asked how Washington would retaliate for the Riyadh attack, he responded cryptically: “You’ll find out soon.”
Earlier on Monday, Trump signalled that US military operations against Iran could continue indefinitely, dismissing questions about a timeline.
“Whatever the time is, it’s OK,” he told reporters at the White House. “We’re already substantially ahead of our time projections. From the beginning, we projected four to five weeks, but we have the capability to go far longer than that. Whatever it takes, we’ll do it.”
He also brushed aside suggestions that he could lose interest in a prolonged conflict. “Someone thought I would get bored. I don’t get bored. There’s nothing boring about this,” he said.