India, Jan. 15 -- Unrest-hit Iran airspace opened on Thursday after a five-hour long closure that the Iranian authorities clamped without explanation, forcing airlines across the globe to reroute their flights.

The airspace closure, which was only for commercial flights, came as tensions remained high with the United States over Tehran's bloody crackdown on nationwide protests and Washington's repeated warnings of military intervention that some officials cited in reports said were "imminent". Track latest in Iran protests here

The Iran airspace allows a shorter routes between continents as the country lies on a key East-West route for airlines. The key East-West airline route is the Europe-Asia air corridor across the Middle East, with...