In comments carried by Iran’s semi-official Fars news agency, the head of the Revolutionary Guards, General Mohammad Ali Jafari, said Iran was capable of imposing “unlimited controls” at the Strait of Hormuz, the entrance to the Persian Gulf and an important oil route.

“The Iranian people will resist with force against the enemies,” Iranian President Mahmoud Ahmadinejad said on state television on Friday. The comments came as the United States set a weekend deadline for Iran to respond to an international offer to freeze its nuclear drive.

The United States and many of its allies have made it clear that they will not tolerate a nuclear-armed Iran. They seem unlikely to abandon this position. On the other hand, President Mahmoud Ahmadinejad has reasons to remain defiant. He has staked his political fortunes and Iran’s national pride on the issue.