Iran temporarily closed its airspace to most incoming and outgoing flights on Wednesday night due to escalating tensions with the United States, according to a notice issued by the Federal Aviation Administration.

The restrictions are scheduled to be in place from 10:15 pm Wednesday to 12:30 am UTC Thursday, the notice said. Subsequently, the time was extended from 1:14 am to 3:30 am (UTC).

Real-time data provided by flight tracker FlightRadar showed that the plane was flying near Iranian airspace as of 8:30 a.m. ET.

The order exempts international flights to and from Tehran, provided they receive prior approval from Iran’s Civil Aviation Authority.

The airspace closure comes as U.S. President Donald Trump threatens to intervene following a deadly crackdown on anti-government protests in Iran, escalating tensions.

Trump later appeared to soften his tone. Speaking at the White House on Wednesday night, Trump said he had received assurances that the killing of protesters in Iran had stopped and that he would “watch and learn” about possible U.S. military action.

The United States has withdrawn some personnel from U.S. military bases in the Middle East as Iran threatens to attack the sites if Washington launches an attack.

Several airlines have canceled or rerouted flights to Tehran in recent days. India’s largest airline IndiGo said on Thursday that some of its international flights would be affected by the closure of Iranian airspace.

Earlier this week, Germany warn Its airlines object to entering Iranian airspace. this Lufthansa Group It said on Wednesday it would bypass Iranian and Iraqi airspace until further notice and canceled some flights.

The United States has banned all U.S. commercial flights over Iran. Airlines such as Emirates, Qatar Airways and Turkish Airlines have also Cancel multiple flights Went to Iran this past week.