The lawmaker, Aladin Borujerdi, who chairs the parliamentary national security and foreign policy commission, said Siemens had sold Iran equipment for its nuclear programme that contained mini-explosives, Iranian media reported Sunday.

"Intelligence-security apparatus succeeded in discovering explosives in equipment which were provided to us for our nuclear activities," Borujerdi said in an interview with parliament's ICANA news website (www.icana.ir/NewsPage.aspx?NewsID=206727).

"The explosives were to blow up when activated to disrupt the whole system. Domestic experts nullified the plot of the enemy, however," he was quoted as saying by ICANA.

"The company Siemens, which provided this equipment, must answer for its action," he said.

Siemens spokesman Alexander Machowetz categorically denied the charge, telling AFP: "Siemens maintains no business dealings in connection to the Iranian nuclear programme and delivers no equipment to this end."

Iran's Press TV carried the story on its website, but no other state media reported on the claim.

Iran often alleges sabotage attempts by Western or Israeli intelligence services, but provides little in the way of evidence.

The Islamic republic, however, has suffered the assassination of four of its nuclear scientists in the past two years, attacks it has blamed on Israel, the United States and Britain.

It has also been targeted by sophisticated computer viruses, such as Stuxnet and Flame, that have spied on its activities or wiped out data related to its controversial nuclear programme.

Tehran maintains the programme is for peaceful purposes, but Western powers accuse it of seeking to develop nuclear weapons.

Should Israel and Iran engage militarily, "nothing is predictable... and it will turn into World War III," Brigadier General Amir Ali Hajizadeh told Iran's Arabic-language television network.

Hajizadeh, who is in charge of Revolutionary Guards missile systems, said: "In circumstances in which they (the Israelis) have prepared everything for an attack, it is possible that we will make a pre-emptive attack. But we do not see this at the moment."

He added that Iran would deem any Israeli strike to be conducted with US authorisation, so "whether the Zionist regime attacks with or without US knowledge, then we will definitely attack US bases in Bahrain, Qatar and Afghanistan."

He warned that Israel "cannot imagine our response -- and it will sustain heavy damage and that will be a prelude to its obliteration."

On Saturday, the head of the Revolutionary Guards, General Mohammad Ali Jafari, said war between Iran and Israel "will eventually happen, but it is not certain where and when."

It was the first time a senior Iranian official had acknowledged a probability of war breaking out between the two arch-foes.

Jafari, quoted by the ISNA and Fars news agencies, also said such a conflict would lead to the annihilation of Israel.

"If they begin (aggression), it will spell their destruction and will be the end of the story," he said.

On Sunday, Jafari's deputy, Brigadier General Hossein Salami, told Fars in an interview that Iran's "defensive strategy is based on the assumption that we will engage in a war, a massive battle against a global coalition led by the US."

He said the Islamic republic had made preparations to "crush" the enemy by hitting "enemy bases in the region, the security of the Zionist regime (Israel) and the energy market, as well as the lives of enemy forces."

He added: "We will not start a war. But if someone wages war against us, we will launch continuous offensives."

Tensions have risen significantly in recent weeks, with Israel threatening to unleash air strikes on Iranian nuclear facilities.

Israel believes Iran's nuclear programme to be aimed at developing an atomic weapons capability that would menace its existence and its current status as the Middle East's sole, if undeclared, nuclear weapons power.

Iran insists that its atomic programme is exclusively for peaceful, civilian ends, but it is locked in a deepening stand-off with the UN nuclear watchdog and the UN Security Council over the issue.