Iran issued a notice, known as a NOTAM, on Wednesday closing its airspace to all flights except international civil arrivals and departures with prior permission from Iran's aviation authorities. The NOTAM was initially extended through 10:30 p.m. ET but then expired.

With its western border with Afghanistan already volatile, officials warned that Pakistan could not afford fresh turbulence along its long and sensitive frontier with Iran.

Iran's key retaliatory leverage is the disruption of the Strait of Hormuz, which could affect 20 percent of global oil and gas trade, though this would be a last resort, as it could disproportionately affect Iran's own oil trade, S-RM said in an analysis provided to Newsweek .

Iran's crackdown on the demonstrations has killed at least 2,615, the U.S.-based Human Rights Activists News Agency reported. The death toll exceeds any other round of protest or unrest in Iran in decades and recalls the chaos surrounding the country’s 1979 Islamic Revolution.

The UK has shut its embassy in Iran as tensions grow over security forces’ lethal crackdown on protests and speculation about US action in response.

The third season of the Israeli series, rescheduled amid the recent surge of conflicts in the Middle East, finally premieres on Apple TV.

The videos that have trickled out of the Islamic Republic offer a rare glimpse into the scope of the crackdown.

An NGO said over 3,400 have died in Iranian regime's crackdown on the anti-government protests across the country. Meanwhile, all eyes are on Trump next move as some officials reportedly said an attack by US is imminent while President said he is "waiting and watching".