Iranian and Iraqi ground forces clashed yesterday at two points hundreds of miles north of the main battle raging outside Basra, according to reports from both sides, raising the possibility of a new front in the current fighting.

Heavy combat continued in the south, where each side said it killed or wounded hundreds of enemy soldiers. Iran's invasion force apparently was making little headway, but some U.S. officials suggested privately that Iran probably had not yet committed all of its troops to the fighting there, Washington Post staff writer Michael Getler reported. The officials added that a powerful new Iranian push could come within several days.

Tehran radio said that Iraqi warplanes bombed the city of Hamadan in western Iran during a prayer meeting, killing at least 73 persons and wounding 350. Iraqi air raids hit a school and civilian targets in other cities as well, Iran charged.

Iranian Foreign Minister Ali Akbar Velayati, appearing to contradict previous statements, was quoted as saying that Tehran did not insist on the overthrow of Iraqi President Saddam Hussein as a condition for making peace. Velayati said Iran had only made "recommendations" that the Iraqis topple their "fascist regime," the French news agency Agence France-Presse reported.

The new fighting reportedly erupted in the highlands around the center of the Iranian-Iraqi border. Informed U.S. officials said that three Iranian divisions were in the area and might eventually try to cross into Iraq.

The larger of the two clashes took place around the Iranian border city of Qasr e Shirin, on the road to Baghdad about 100 miles from the capital. Tehran radio said that Iranian forces beat back an overnight Iraqi attack there and also reported "violent" fighting more than 150 miles to the south around Dehloran.

The Iraqi News Agency said "skirmishes" broke out at several points along the border, particularly along the central front and near Dehloran, saying that 39 Iranians were killed. It accused Iran of shelling residental areas and economic targets in Khanaqin, an Iraqi border town near Qasr e Shirin.

It was unclear whether Iraqi forces were inside Iran along the central front or had shelled Iranian towns from beyond the border. While Iraq claimed last month that it had withdrawn all of its troops from Iran, Tehran has accused the Iraqis of holding onto some strategic positions inside the country.

Reports from the Basra front remained contradictory, although military reports in Tehran acknowledged that Iranian troops had failed to make any new territorial gains. A U.S. State Department official said in a background briefing that, "to the best of our knowledge," fighting yesterday was "quite heavy."

Iranian troops drove across the extreme southeastern border late Tuesday in an apparent drive toward Iraq's second-largest city, Basra. By capturing it, Iran would effectively cut off Iraq from the Persian Gulf and capture its principal facilities for loading oil on supertankers.

Sources at both the Pentagon and State Department suspect that the main thrust of the Iranian attack probably is not yet under way, staff writer Getler reported.

Based upon delayed and incomplete intelligence information reaching here, sources described the battlefield situation as basically static in the past 24 hours.

The Iraqis, these sources said, had managed to push back portions of the initial Iranian thrust. But a number of specialists said that some of the Iranian attacks might have been "probes" of enemy defenses rather than full-scale assaults and that the Iranians may have rushed in too far too fast. Thus, they said, it was hard to say if the Iraqis were scoring real success in counterattacks.

The fighting, they said, was still going on inside Iraq but at distances of only three and six miles from the border.

At the State Department briefing, the official talked cryptically of the Iranian "invasion or attempted invasion." He said there were approximately 100,000 troops on each side in the main battle area in southeastern Iraq and that a "very substantial number is engaged in the present fighting."

But officials at the Pentagon tended to disagree with portions of the estimate presented at the briefing. These sources suggested that the bulk of the Iranian force in the immediate vicinity--perhaps more than half of it--has not yet been committed to the battle.

These troops, the sources say, are still inside Iran and are generally on the northern edge of the Basra front. Some analysts expect these troops, and possibly others brought in from other locations, to launch a major new attack. They are said to be supplied with river-crossing equipment, which would be necessary to bridge the Shatt al Arab waterway to reach Basra.

Some State Department officials also subscribe to the possibility that the initial Iranian attacks are "probes" and that Tehran has not yet put in everything they have.

Baghdad said in a military communique that its forces had "intercepted" a new Iranian thrust and "totally destroyed" the enemy forces. Repeating claims made Thursday that Iranian troops had been driven out of the country, the Iraqi press printed victory messages sent by Iraqi officers to Saddam Hussein. The Iraqi News Agency said that celebrations and rallies to express support for the president continued throughout the country.

In more than three full days of fighting, Iraq claimed to have killed 6,070 Iranians, destroyed 107 tanks, 41 troop transports, 46 vehicles and 10 cannons. Iraq also said that it shot down an Iranian plane--the third that it has claimed since the invasion--during a dogfight over the western Iranian town of Ilam.

Tehran radio said that Iranian forces had successfully beaten back all Iraqi counterattacks and launched a "vast counteroffensive." During fighting yesterday, Iran said 200 Iraqis were killed or wounded, 56 tanks and troop transports destroyed and 11 tanks captured intact.

Iran said that Iraqi air raids destroyed more than 150 homes in Hamadan and the western cities of Ilam and Eslamabad. It said that its warplanes struck Iraqi troop positions in the south.

Iranian spiritual and political leader Ayatollah Ruhollah Khomeini, in a message on "Jerusalem Day" read by his son at Tehran University, said that his country would fight until Iraq agreed to pay war reparations and admitted that it was originally the aggressor when it invaded Iran in September 1980.

While he dropped any specific call for toppling Saddam Hussein, Khomeini urged the overthrow of Iraq's ruling Baath Party and an Iranian march through Iraq eventually to "liberate" Jerusalem.

Hundreds of thousands gathered at the university to hear Khomeini's message, AFP reported from Tehran. Participants trampled on crude replicas of the American flag and carried banners proclaiming, "The road to Jerusalem goes through Baghdad."

Foreign Minister Velayati, in Cyprus for a meeting of the Nonaligned Movement, said Iran launched its invasion only to push Iraqi artillery out of range of Iranian territory. At the start of the offensive, however, Khomeini appealed strongly to Iraqis to join forces with the invading Iranians and overthrow Saddam Hussein.