TEHRAN, (Reuters) – Iran’s Revolutionary Guards warned the United States on Wednesday it would face a “tragedy” if it attacked the Islamic Republic.

“We advise U.S. officials to be careful not to face another tragedy,” Mohammad Hejazi, a senior commander of the elite Guards, was quoted as saying by the official IRNA news agency.

“Our last word is that if you want to move towards Iran make sure you bring walking sticks and artificial legs because if you came you will not have any legs to return on,” he said.

Hejazi’s comments followed market talk of a military strike against the country’s nuclear sites.

The standoff between the West and Tehran has sparked fears of a military confrontation that would disrupt oil supplies.

Last week a report said Israel had practiced for a possible strike against Iran’s nuclear facilities.

Washington says it is focusing on diplomatic pressure to thwart Iranian nuclear work it suspects is aimed at making bombs but has not ruled out military action if that were to fail.

A senior Iranian official on Tuesday denied market rumours of an Israeli attack on one of Iran’s nuclear facilities, which Tehran says are part of a peaceful drive to generate electricity.

The New York Times last week quoted U.S. officials as saying Israel had carried out a large military exercise, apparently a rehearsal for a potential bombing of Iran’s nuclear facilities.

Many analysts say Iran’s nuclear sites are too numerous, distant and fortified for Israel to take on alone. They say the United States could unleash vastly superior firepower if it attacked Iran but that Tehran could strike back against its forces in Iraq and disrupt oil supplies vital to the world economy.

Also on Wednesday, the influential speaker of Iran’s parliament hit out at the European Union for imposing new sanctions despite diplomatic efforts to end the dispute.

The 27-nation EU on Monday agreed new punitive measures targeting businesses and individuals the West says are linked to Iran’s nuclear and ballistic programmes, ten days after world powers offered incentives to Tehran in a bid to resolve the row. “If you want to negotiate with Iran on the proposed package, why are you following the path of confrontation … ,” speaker Ali Larijani, Iran’s former chief nuclear negotiator, said.

EU foreign policy chief Javier Solana handed Iran an offer on June 14 of economic and other benefits proposed by the United States, Russia, China, Britain, Germany and France to try to convince it to halt uranium enrichment.

Iran has repeatedly ruled out suspending enrichment, which can have both civilian and military uses. Their refusal to do so has drawn three rounds of limited U.N. sanctions since 2006.

Iran has put forward its own package of proposals aimed at resolving the row, but diplomats say it ignores global concern about its enrichment programme.