The United States needs to put up a smoke screen ... and has launched a campaign of intimidation that talks about attacks against Iran and Syria so as to deflect attention from its searing defeat in Iraq," said the Hezbollah chief Hassan Nasrallah on Friday, whose militant group is backed by Iran and Syria.
The Shiite leader was speaking via video link at a rally in his Beirut stronghold honouring Hezbollah martyrs.
"Whoever dares to launch war against Iran will be met with doubly that force," he warned. "Iran is strong; Iran is powerful and has a leader unique to the whole world."
He added that any military action against Iran or Syria would engulf the entire region.
His speech came amid renewed pressure on Iran by the international community over its nuclear programme and against Syria over its brutal crackdown against an eight-month pro-democracy revolt.
Nasrallah said both countries had been against the US-led invasion of Iraq in 2003, and Washington was now keen to make them pay for that as the roughly 31,000 US soldiers remaining in Iraq prepare to leave the country before the end of the year.
He also accused the United States of using double standards when it comes to the UN-backed court probing the 2005 assassination of Lebanon's ex-premier, Rafiq Hariri.
Nasrallah said he saw no reason why Lebanon should be expected to contribute its share of the tribunal's funding given Washington's decision to cut off funds to the United Nations cultural agency UNESCO after members voted to admit Palestine as a full member.
"Isn't the funding of UNESCO an international obligation for the US?" he said. "Why can it shirk its obligation and not Lebanon?"
"If Lebanon doesn't fund this unconstitutional and illegal court, Feltman comes along and threatens sanctions," he added, referring to Jeffrey Feltman, the US assistant secretary of state for Near Eastern affairs.
Lebanon's government is dominated by Hezbollah and its allies, which are insisting that the country cease all cooperation with the Netherlands-based Special Tribunal for Lebanon (STL), set up in the wake of Hariri's murder.
The STL has charged four Hezbollah operatives in connection with the assassination.