Iran and Iraq appeared locked in total disagreement over a cease-fire call from the U.N. Security Council today and pressed on in unabated fighting for control of key Iranian cities along the Shatt-al-Arab waterway.

Two Iranian F4 Phantom jets divebombed a vital bridge over the waterway at this island about noon, underscoring the strength of Iran's continuing resistance despite Iraqi successes that included a tightening siege on Abadan and Khorramshahr, near here, and claims of fresh advances at Ahwaz and Dezful, to the north and about 50 miles within Iranian territory.

President Saddam Hussein of Iraq announced early today on official Iraqi television that his military "has reached its goals" in Iran and that Iraq consequently is willing to sit down at the negotiating table with Iran, "but only from a position of strength."

The Iraqi president, wearing a field marshal's uniform and sitting before a giant map of the region, proclaimed Iraq "the sword of the Arab people" and said the main condition for peace is that Iran return to the Arabs all "usurped lands," including three tiny islands near the entrance to the Persian Gulf that the late shah of Iran took from the Arab sheikdoms of Ras-al-Khaimah and Sharjah in 1971.

"The time is over when Iran was the watchdog of the gulf," Hussein said in accepting the Security Council's call for an end to the fighting and a beginning of peace talks, provided Iran also agrees to the conditions he laid down.

There was no immediate official reaction from the Iranian government to the U.N. appeal or to Saddam Hussein's offer of talks. But the conditions set by the Iraqi leader seemed likely to draw continued rejection from the Islamic leadership in Tehran.

An indication of the official attitude came from Hojatoleslam Ali Akbar Hashemi Rafsanjani, the speaker of the Iranian parliament, who, according to agency reports from Tehran, told a news conference:

"There is no question of a cease-fire for us."

Rasanjani also declared that despite the U.S.-sponsored embargo against Iran because of the U.S. hostages there, Iran has been getting spare parts for its military equipment "quickly in recent days" from world markets and what he described only as neutral countries.

U.S. military analysts in Washington have said a key to Iran's ability to continue its stiff resistance to Iraqi attacks is a supply of spare parts for its U.S.-equipped military.

The Iranian air attack on this island, in the Shatt-al-Arab a few miles upriver from the Iraqi port of Basra, seemed to dramatize why Iran is not yet ready for negotiations. The evidence here is that the Iranian armed forces are still far from beaten despite Iraqi confidence that they now have the upper hand in the eight-day war.

Reports from the front inside Iran's Khuzestan Province east of there indicated that despite a rapid movement up to the outskirts of Ahwaz, the provincial capital 50 miles from the Iraqi border, the Iraqis have yet to capture any of the main strategic cities in the besieged province.

At Ahwaz, Iraqi and Iranian artillery units were engaged in a shelling duel over the city. According to one eyewitness report, Iran was giving as much as it was getting. Iraqi soldiers also had yet to try to enter Ahwaz despite reports to the contrary, the witness said. In the south, Iranian resistance also was continuing at the besieged river port of Khorramshahr and the nearby oil refinery complex at Abadan.

The target of today's Phantom attack on the island here was the four-month-old Khalid ben al-Walid Bridge, which straddles the river over Sindbad Island. The bridge is a lifeline of the Iraqi armed forces, which advanced down the river's left bank to Khorramshahr and Abadan before looking north to attack Ahwaz.

The bridge has been one of the Iranian Air Force's man targets in the Basra area since the war between the two OPEC nations began. Iranian jets have made dozens of raids on it in an attempt to stall the Iraqi Army's logistics flow toward Iran.

As on the previous Iranian raids on the bridge, however, the bombs went wild, though not without causing damage. One of the two 250-pound bombs from the first Phantom slammed into an Iraqi coastal utility vessel tied up at the island's docks. The bomb hit the ship just below the bridge, setting fuel tanks afire and incinerating a smaller river boat tied alongside.

A second bomb landed nearby unexploded and two bombs from a second jet bracketed the end of the bridge, one gouging up a blacktop road, the other falling into the water with a blast that sent hundreds of fish belly-up and dead drifting down the green waters to the gulf.

The impunity with which the two Iranian Air Force jets penetrated Iraqi's air defenses and the ease with which they flew off leaving the vessel belching out a column of ugly black smoke belied Iraqi claims of control of the war. Indeed, all along the contested Shatt-al-Arab that divides the two waring nations south of here, the fighting seemed to be continuing much as it has since the first days of the conflict last week.

Sixty miles from Basra, at the Iraqi oil depot town of Al Faw, on the far right bank of the river where it spills into the gulf, artillery dug in across the waterway in Iran behind a line of date palms pounded oil storage tanks here for the seventh straight day, setting afire at least five of them.

Iranian jets also were reported by Iraqi military officials to have knocked out Iraq's oil-loading terminal at Al-Bakr, 25 miles to the south in the gulf tself.

Further up the Shatt-al-Arab toward Basra, Iraqi artillery gunners continued to pour shells into the oil refinery of Abadan, setting a previously untouched corner of the vast oil complex aflame.

Viewed from the Iraqi side of the river it is evident that there are still parts of the refinery, the world's fourth largest, which have not been destroyed. But the orange flames that shot up as high as 200 feet into the air before turning into heavy black thunderheads of smoke, rising thousands of feet higher, were evidence that part of the complex was being eaten up by fire.

Across from Khorramshahr a few miles further up the river, Iraq also was moving in reinforcements of artillery, antiaircraft guns and mobile BM21 multiple rocket-launchers into place around its positions among the palm groves.

Fighting was still going on around the town, and it appeared tonight that Iraq was strengthening its positions in the hopes of delivering a telling blow to the Iranian soldiers and Revolutionary Guards, who have refused to surrender despite the fact some Iraqi units have been on the city outskirts for days.

The Associated Press, reporting from near Qasr-e-Shirin at the northern end of the Iraqi invasion front, said Iraq was moving troops and armor southward, apparently amassing equipment for a reinforced drive to take Khorramshahr and Abadan.

In the gulf, Iran's Navy claimed it had control over its coastline as far south as the Strait of Hormuz and that Iraqi ships had been forced to seek refuge in the ports of other Arab countries along the Persian Gulf.

In a reflection of broad Arab support for Iraq, Prime Minister Mohammed Ali Rajai said over Tehran radio that Iran will consider Arab states "as being in a state of war" if they aid Iraq. He specified Abu Dhabi, Kuwait and Jordan.

"Responsibility for a future war, in which they are involved because of their policies, must be borne by the countries that are helping Iraq by air, on land and at sea by various means," he said.

In a reflection of mounting tension along the vital waterway, the British Defense Ministry announced in London the dispatch of a guided-missile destroyer and a support ship to the nearby Indian Ocean.

An official source said the two ships -- the destroyer Coventry and the support ship Olwen -- would be on standby to move to the Persian Gulf if required. No decision had been made on any kind of intervention, the source stressed, adding that Britain wants "as flexible a stance as possible" in case the Iranian-Iraqi war grows into a border crisis in the gulf.