Iraq claimed yesterday that it had crushed two Iranian divisions in the past week of fighting in the Persian Gulf war, and U.S. analysts offered evidence supporting a substantial setback to Iran's week-old invasion into Iraqi territory.

News agency reports from Baghdad and Tehran indicated that fierce artillery and tank duels took place around the oil port of Basra, and Iraq reportedly launched repeated air and tank assaults against Iranian positions.

An Iraqi communique said Baghdad's troops killed 349 Iranian soldiers and destroyed 11 tanks. It also said Iraq destroyed two large "naval targets" in the Khawr e Musa channel leading to the port of Bandar Khomeini at the head of the Persian Gulf, Reuter reported.

Tehran radio reported that two Iraqi counterattacks were repelled by Iranian forces in the western part of the front inside Iraq. The radio said Iran killed or wounded 200 Iraqi troops yesterday and seized 28 tanks and three bulldozers.

Both countries have prevented foreign correspondents from going to the front, so the conflicting casualty claims could not be verified independently.

According to intelligence reports reaching Washington, however, Iraqi troops have pushed the Iranians back to a point where their deepest penetration into Iraq is only 2 1/2 miles from the border.

According to these delayed reports, which reflect the situation as of Monday, the initial Iranian invasion force--estimated to involve about 30,000 troops--is having trouble replacing the soldiers lost in battle and is running short of ammunition.

Sources here say a resupply effort is under way, with truck convoys heading south from Dezful and Ahvaz. These convoys are being protected from the air with U.S.-built F4 and F14 Iranian Air Force jets.

American specialists said it will be several days, however, before the supplies reach the border near the front lines in the southeastern corner of Iraq, opposite Basra. It therefore seems unlikely, analysts here say, that the Iranians will be in a position to mount any further large-scale assault in that region for a while.

Since withdrawing from Iran to comply with a self-declared cease-fire in the 22-month-old war, Iraqi troops have been redeployed along the 700-mile border. The Kuwaiti daily Al Qabas reported from Baghdad Monday that Iraq has deployed only 25 percent of its estimated 210,000-man Army to defend Basra, The Associated Press reported.

According to U.S. analysts, both sides have major elements in the area--perhaps approaching 100,000 troops apiece--that have not been committed to the fighting.

Since the fresh fighting began July 13, sources here say Iran has launched three major assaults in the direction of Basra but with minimum gains. The Iraqis counterattacked last Wednesday, Thursday, Saturday and Sunday and in those attacks, sources here say, it now appears that "Iranian units got pretty badly mauled," as one analyst put it.

The original Iranian strategy, they said, appears to have been to launch the initial attack as a less than all-out assault, hoping to draw Iraqi forces being held in reserve into the battle for Basra. Then, a larger Iranian force would sweep around the flank from the north and try to trap the Iraqis between the border and the Shatt al Arab waterway at Basra.

The Iraqis, however, did not commit their reserves.

Iran is still holding this larger force, which was expected to carry out the flanking maneuver, in reserve slightly to the north of the current fighting. This force also has river-crossing equipment with it, but officials say they do not know how well-supplied those troops are now with other equipment.

Although the anticipated offensive from this force has not materialized,U.S. officials cautioned that it still could be launched.

There are also three other Iranian divisions much farther north along the border that could cross over into Iraq opposite the Iraqi capital of Baghdad.

Analysts here said Iraqi forces also have suffered heavy losses and are fatigued from the repeated Iranian assaults.

Officials here are also taking seriously warnings from Iranian officials being broadcast over Tehran radio cautioning that if arms continue to move across the borders of other countries into Iraq, then Iran will have the right to make an "appropriate response." It is known that trucks with equipment for Iraq are moving across the border from neighboring Kuwait into Iraq.

The United States has said that what is most worrisome about the heated-up Iranian-Iraqi war is the possibility that it could spill over into the pro-Western states in the Persian Gulf. The State Department said last week that the United States was prepared to hold joint military exercises with any of the gulf states that felt threatened by the war.

Thus far, however, American officials say the gulf states have not shown any interest in such exercises.

Meanwhile, Reuter reported from Baghdad that Iraq claimed to have killed 10,000 Iranian soldiers since the war heated up a week ago.

The figure was announced by Deputy Prime Minister Tariq Aziz, who told a news conference: "Iran's offensive has been crushed and they have suffered heavy losses."

At the same time Aziz said Iraq was ready to enter negotiations, direct or indirect, with Iran.

Agence France-Presse reported from Tehran:

In a rare indication of the location of the fighting, the newspaper Ettelaat reported that Iranian forces had reinforced their positions inside Iraq south of the Iranian border point of Kushk, about 35 miles north of Basra and less than 20 miles from the Baghdad-Basra highway.

Most recent reports have referred to consolidation of positions, mopping-up operations inside occupied enemy areas and heavy Iraqi losses incurred in counterattacks.

In a similar counterattack Monday, the Iranian press reported, Iraq tried to drive forward in four successive waves for more than eight hours with two armored and two mobile brigades, before giving up after heavy losses.

In the initial hours of the invasion, reports said Iranian forces pushed into Iraq on three main axes. One communique said they had progressed 15 miles toward Basra, getting to within four miles of the strategic city.

Meanwhile, the determination of the Iranian leadership to pursue the Persian Gulf war until Iran's conditions are met appears firm, observers here said. Iran has demanded war reparations and the removal of the Iraqi head of state, Saddam Hussein.