An IndiGo flight travelling from Tbilisi in Georgia to Delhi was reportedly the last non-Iranian aircraft airborne before Iran abruptly closed its airspace on Thursday amid rising unrest in the region.

Shortly after the closure, Indian carriers IndiGo, Air India and SpiceJet cautioned passengers about possible flight disruptions due to the sudden restrictions.

Iran issued a Notice to Airmen (NOTAM) early on Thursday, suspending most air traffic and allowing only a limited number of approved international flights. Flight-tracking data showed the skies over Iran and neighbouring Iraq rapidly clearing as airlines diverted or cancelled routes ahead of the directive.

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Iran extended an order closing its airspace to commercial aircraft without explanation early Thursday as tensions remain high with the United States over Tehran’s bloody crackdown on nationwide protests.

A notice to pilot said the closure was estimated to last until 7:30 a.m. local time. A previous order had closed the airspace for just over two hours.

The Iranian government offered no explanation of the decision to shut its airspace.

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The United States requested an emergency meeting of the U.N. Security Council on Iran on Thursday afternoon, a council diplomat said, speaking on condition of anonymity because the meeting has not yet been scheduled.

The security force crackdown on the demonstrations has killed at least 2,586, the U.S.-based Human Rights Activists News Agency reported. The death toll exceeds that of any other round of protest or unrest in Iran in decades and recalls the chaos surrounding the country’s 1979 Islamic Revolution.