Iraq today pushed its drive into neighboring Iran to the outskirts of Ahwaz, the capital of Iran's oil-rich Khuzestan Province, as the six-day-old war continued to deal crippling blows to the vital oil economies of the two Moslem countries.

While Iraqi forces fought to dislodge the last remaining Iranian defenders holding out in the devastated oil city of Abadan and the port of Khorramshahr, Radio Baghdad today claimed that its troops had pushed 50 miles into Iran and captured Ahwaz.

Although the official Iranian state radio vehemently denied the Iraqi claim, calling it "a great lie," the official Pars News Agency gave it some substantiation by acknowledging that 28 persons had died in fighting in the provincial capital of 300,000.

Reuter reported from Tehran that an Ahwaz state radio official, reached by telephone, said that "many people have been killed, and houses have been destroyed," then hung up, saying air raid sirens were blaring. Reuter quoted an operator at the Ahwaz telephone exchange as saying that artillery shells were exploding near the building.

Ayatollah Ruhollah Khomeini, in a message broadcast by Iran's national radio, said his country was ready "to fight to the last soldier" to repel the Iraqis and, if necessary, "we are ready to send all our children to battle the thugs." The Iranian ruler said that "if the enemy enters a city, he should find all the inhabitants up in arms to face him."

The latest battle reports came as Oil Ministry officials in Baghdad told foreign oil clients that because of damages to its oil installations around the country, Iraq would be unable to make deliveries until further notice.

The latest blow to the Iraqi oil industry, one of the world's largest, came earlier today when saboteurs in Turkey blew up one of Iraq's two working pipelines to the Mediterranean. Oil sources earlier reported that supplies through the other pipeline, which goes through Syria and branches off to ports there and in Lebanon, had stopped because of Iraq's need to preserve remaining oil supplies for domestic and military use.

On Friday, Iranian warplanes bombed the cities of Mosul and Kirkuk in northern and central Iraq, damaging the country's last important oil facilities. Iranian planes also attacked a major refinery in Baghdad for the third time, but Western observers said stiff resistance from anti-aircraft batteries there appeared to prevent serious damage.

The one week of war now has taken about 3.5 million barrels a day off the world market. Before the hostilities, Iraq was exporting about 3 million barrels a day and Iran, whose oil facilities were slipping into chaos, about 500,000 barrels.

With Iran's vast oil complex at Abadan and the Khorramshahr port in flames and its main oil loading port on the Persian Gulf at Kharg Island also damaged by bombs, Iran's exports have been halted and it appears unlikely that, even were the war to end soon, production and delivery of oil could resume quickly.

One sign of the two countries' sudden shortage of oil, which previously had made them rich and influential nations, has been the sudden reduction of their air warfare in the last two days.

In the first days of the war, both the Iranian and Iraqi air forces flew over each other's territory almost at random, bombing oil installations, military bases and often civillian centers.

Today, Iraqi planes flew only a few missions and Iran's Air Force, after the two bombing runs over Baghdad in the early morning, was also limiting its operations, presumably to conserve diminishing jet fuel supplies.

While there were no reports of gasoline shortages in Baghdad, there were signs of near panic in Basra and cities more closely involved in the fighting. For the first time, automobile lines were forming at filling stations as nervous civilians sought to stock up before rumored rationing is imposed.

The shortages are unlikely to ease soon if peace is finally restored.

The damage to the oil facilities in Iran and Iraq will take years -- and billions of dollars -- to repair. News services reported the following:

Turkey's minister for energy and natural resources, Serbulent Ringol, confirmed that a portion of the Iraqi-Turkish pipeline had been blown up early today and he said three suspects had been arrested.

The site of the blast was near Silopi, a town about eight miles from the Iraqi border. The 600-mile-long pipeline, which connects Iraq's northwestern oil fields with the Turkish Mediterranean port of Yumurtalik, has been a frequent target of saboteurs and has been damaged a half-dozen times this year by bombs.

Raif Eris, director of the company that operates the pipeline, told Washington Post special correspondent Metin Munir in Ankara that it would take his crews two or three days to repair the pipeline, and that tons of crude oil had been lost in a blaze started by the explosion.

Until the explosion, Eris said, deliveries through the pipeline had continued "more or less according to schedule" despite the war.

Authorities in Ankara refused to comment on reports that the sabotage could be the work of Kurdish secessionist, terrorist groups active in the region where Syria, Turkey, Iraq and Iran converge, Munir reported.

In Damascus, a spokesman for the Syrian Oil Ministry said the pumping of Iraqi petroleum across Syria to Banias had stopped today because of Iranian air strikes on Iraqi oil installations.

He said Syria had agreed on Thursday to an Iraqi request to resume pumping crude through another pipeline crossing Syria to Tripoli on the Lebanese coast, but there was no indication that Iraq, attempting today to conserve fuel, was using that pipeline, which had been idle for four years.

In what was believed to be the first official Syrian commentary on the Iraqi-Iranian conflict, the state-run Damascus Radio accused the United States of planning to intervene militarily in the Middle East and said Syria had approached other countries to end the fighting between Iraq and Iran.

"People in the region should resist firmly designs being hatched by the U.S., some of its Western allies and Israel for direct military intervention and joining forces under the pretext of ensuring Gulf security and protecting oil flow," the Syrian statement said.

Meanwhile, Hassan Nazih, first head of the National Iranian Oil Co. after the takeover by Khomeini but now a strong opponent active in the exile opposition movement in France, said in an interview in Paris with Ronald Koven of The Washington Post that his information from Iran is that the vital parts of the huge Abadan refinery and the oil export terminal on Kharg Island have not been damaged, although there are spectacular fires in oil storage tanks that were hit in the complexes containing both installations.

Even if Abadan were entirely knocked out, Nazih said, Iran, which has many smaller refineries scattered throughout the country, could manage domestically, with some rationing and energy substitution.

Strikes in the oil fields before the Khomeini takeover had taught Iranians how to make do with relatively little oil, Nazih said.