Iran again imposed a nationwide flight ban, the civil aviation authority said on Sunday, in an announcement that came only briefly before the closure began.'From 9 pm (1730 GMT) tonight until 6 am all flights in the country have been cancelled,' a spokesman for the authority said, according to a report by news agency, citing 'operational restrictions.'Iran closed its airspace for almost 48 hours last week, after firing a barrage of missiles at Israel. Even after the closure was lifted, there were almost no international flights into and out of Tehran, likely due to fears of an impending Israeli counterattack.Source: Ghana News Agency