The US has ordered a second aircraft carrier group, the USS Nimitz, to head to the Middle East as tensions ramp up over the Iran-Israel conflict.

The Nimitz, the oldest of America’s nuclear-powered aircraft carriers, left the South China Sea, where it was supposed to arrive at central Vietnam later this week.

Its course changed Monday for the Middle East due to “an emergent operational requirement,” sources told Reuters.

The aircraft carrier’s new heading was flagged by the ship-tracking website Marine Traffic.

The US military has also moved a large number of refueling aircraft to Europe to provide options to President Trump for aerial operations in the region, officials told Reuters.

The Truman made back-to-back headlines in April and May when two of its $60 million fighter jets fell into the Red Sea during evasive maneuvers to avoid incoming attacks from the Iran-backed Houthis in Yemen.

America’s commitment to maintaining multiple aircraft carriers in the region comes as tensions continue to escalate on the fourth day of missile exchanges between Israel and Iran.