The U.S. has ordered the evacuation of some personnel from its largest base in the Middle East as President Donald Trump weighs strikes against the Islamist regime in Iran.

The move echoes similar actions last year in the run-up to the joint U.S.-Israeli air and missile strikes on Iranian nuclear program sites. But a U.S. defense official cautioned this evacuation was a precautionary step as Tehran struggles with mass anti-government protests with security officials killing numerous protesters.

The shift of some forces from Al Udeid Air Base in Qatar comes after Trump told Iranians on Tuesday that “help is on its way,” and warned Americans in Iran they should think about evacuating the country.

A former U.S. official familiar with the situation said aircraft had also been moved. The current and former officials were granted anonymity to discuss a sensitive national security issue.

Reuters first reported the evacuation.

The Qatari government said in a statement Wednesday that the evacuations from Al Udeid “are being undertaken in response to the current regional tensions.”

The Pentagon stations about 10,000 U.S. troops at the sprawling Al Udeid, along with smaller bases in the region in Iraq, Syria and Jordan.

The base has its own air defenses, which were put to the test in June when Iran attacked it with ballistic missiles. But one Patriot missile interceptor that was sent there before the attack has since been shipped back to South Korea.