DUBAI, UNITED ARAB EMIRATES, NOV. 13 -- Iran's Supreme Defense Council today issued a call for all able-bodied citizens to present themselves at new recruitment centers in preparation for a new offensive against Iraq and possible action against the United States.

Ali Akbar Hashemi Rafsanjani, the powerful speaker of the Iranian parliament, declared that the seven-year-old Iran-Iraq war has entered a "completely new phase," involving more active public participation at the 750-mile front with Iraq so that "numerous and consecutive offensives" could be waged. Rafsanjani said the mobilization also was aimed at "the probability of a clash with America in the Persian Gulf."

The mobilization, approved Thursday night by Ayatollah Ruhollah Khomeini, Iran's supreme leader, seemed to reinforce intelligence reports that Iran was preparing a ground offensive on the southern front around the Iraqi river port of Basra, possibly by the end of the year.

In fighting today, Iraq claimed one of its highest daily totals of ship attacks in the war. Baghdad said that, between Thursday night and tonight, its jets hit five "large naval targets," a phrase that usually indicates oil tankers. Iraq said it has hit 11 ships since Monday, but the only confirmed victim has been the Greek tanker Fortuneship L.

According to the Lloyds shipping registry in London, Fortuneship L was hit by an Iraqi Exocet antiship missile Wednesday, then by two more yesterday.

Lloyds said that Iraqi jets tried to make a fourth missile attack on the blazing tanker today but that the missile instead hit a Singapore-registered salvage tug, Semco One, that was trying to tow the tanker.

The tug sank immediately. Two of its crew were killed in the attack, and four were injured. The Fortuneship L's crew of six Greeks and 21 Pakistanis already had boarded a second tug and was reported unharmed.

Iraq's attacks on tankers reportedly have taken place off Iran's coastline, mainly near the main Iranian oil terminal at Kharg Island. Iraq has been attacking Iranian oil facilities and tankers in an effort to squeeze Iran's economy, already hard-pressed to support the war effort.

Iran has been trying to keep up its oil exports by using about 20 chartered tankers or vessels owned by the Iranian Oil Co. to shuttle oil from the frequently attacked Kharg Island to transshipment points at the southern end of the gulf, just inside the Strait of Hormuz.

With its oil lifeline under constant attack and its own ripostes against the shipping of Iraq's tacit Arab allies hampered by the presence in the gulf of U.S. and Western European navies, Iran seems to be considering a renewal of the ground war, in which its troops outnumber Iraq. Iran's Supreme Defense Council said such a strategy is necessary "to speed up the enemy's defeat and ruin," according to a report by Iran's state news agency.

The council "urged those who are personally able to attend the war fronts, to declare their preparedness to . . . be dispatched to the fronts," the report said. The agency added that women, the infirm and others who are unable to serve at the front may each contribute money equal to the cost of keeping a soldier in the field for three months, a practice that was used in Persia in ancient times.

Tehran's new mobilization was seen by analysts here as a reaction to this week's call by the Arab League summit for Iran to agree to an immediate cease-fire in accordance with the terms of a U.N. Security Council resolution approved last July.