Tehran will consider any military action against its nuclear facilities as the beginning of a war, Iran's official news agency IRNA reported Friday.
The commander of Iran's Revolutionary Guards, General Mohammad Ali Jafari, was quoted as saying that any country that attacks Iran would regret doing so.
According to the report, Jafari has warned that such a step would be the beginning of war.
However, the general was also quoted as saying that he considers it unlikely Iran's adversaries would attempt an attack.
In a newspaper interview last week, Jafari warned that if attacked, Iran would barrage Israel with missiles and choke off the strategic Strait of Hormuz, a narrow outlet for oil tankers leaving the Persian Gulf.
Israel carried out a large military exercise last month, seen throughout the media as a rehearsal for an attack on Iran.
U.S. admiral: Iran likely to attack Israel
Meanwhile, a U.S. admiral warned earlier this week that Iran is likely to launch ballistic missiles against Israel and the United States and the NATO alliance should prepare for it.
In recent years, the missile boats of the Sixth Fleet practiced intercepting Shahab-3 missiles from Iran aimed at Israel, along with the Arrow batteries of the air force and U.S. and Israeli batteries of Patriot missiles.
In an article entitled "Maritime Strategy in an Age of Blood and Belief" in the U.S. Naval Institute's monthly Proceedings, fleet commander Admiral James Winnefeld describes the possibility of an offensive barrage of ballistic missiles fired from Iran against Israel as being "by far the most likely employment of ballistic missiles in the world today, and it demands our immediate attention in the event of a need for a U.S. or NATO response."
He says Iran is an "unpredictable adversary," which could be provoked into action "by an isolated, and perhaps seemingly unimportant, event."
Winnefeld's commander, the chairman of the Joint Chiefs of Staff at the Pentagon, Admiral Michael Mullen, mentioned earlier this week during his visit in Israel the presence of missile defense vessels of the Sixth Fleet in the Mediterranean and their role in intercepting Iranian missiles.
One of Mullen's hosts noted at the end of the visit that even though Israel Defense Forces Chief of Staff Gabi Ashkenazi and the other senior officers did not discuss operational coordination, it was mentioned during discussions that both sides would like to avoid mistaken confrontations, of the sort that led to the IDF attack against the U.S. Navy ship, Liberty, in June 1967.
At a briefing to reporters in the Pentagon Wednesday, Mullen discussed his good relations with Ashkenazi and his impressions of the visits with the IDF on the northern border and near the Gaza Strip. "Israel remains a vital and trusted military ally in the Middle East," he said, which faces "very real security threats" and "the tyranny of what I call 'close-quarters geography,'" Mullen said.
The chairman of the Joint Chiefs added that "Iran is still working to develop nuclear weapons" and that the Israeli timetable in relation to Iran's nuclear program is shorter than the U.S's. However, the admiral stressed he is opposed to an Israeli or U.S. strike against Iran.
Such a strike could destabilize the region and open a third front for the U.S. armed forces, while it is preoccupied in Iraq and Afghanistan, he said.
The Iranian regime remains "a destabilizing factor in the area," Mullen said, but in his view the preferred way of resolving the issue lies in international diplomacy and not the use of military force.