Iranian Civil Aviation Organization offers no immediate explanation for disaster; Ukrainian officials have backed off claim it was brought down by mechanical trouble

But expert questions how Iran claimed so quickly after the accident that no foul play was involved; US-Iran tensions likely to hamper probe

Many international carriers say they will avoid flying over Iran and Iraq amid tensions with US, causing significant delays worldwide

US president says immediate sanctions to be imposed on Islamic Republic, vows Tehran will never be allowed nuclear weapons, claims IRGC missiles 'paid for' by Obama administration

With troops now focused on defending themselves and American interests in region, they have been diverted from their mission to put an end to jihadist terror group

No reports of damage to Bushehr facility following 4.5 magnitude quake in area, the second temblor in 2 weeks

Move comes as Iran launches rocket barrage at US bases in Iraq, and Ukrainian plane crashes outside Tehran airport due to engine fire

Boeing 737 leaves Tehran's international airport for Kyiv, crashes shortly after takeoff, killing everyone on board

Islamic Republic's Jewish community issues statement saying 'God will avenge the blood' of slain general after US assassination

Official says Washington anticipating 'major' attack by Iran, possibly targeting an American commander; US air force seen readying forces for possible war