MANAMA, Bahrain (AP) _ An American-operated supertanker loaded with Iranian oil hit a mine Monday just outside the Persian Gulf, and three reflagged Kuwaiti ships were reported moving slowly toward home under U.S. Navy escort.

Iran says the gulf will be ''full of mines'' until the superpowers quit intervening in the region, where Iran and Iraq have been at war since September 1980. Iran declared Monday it would turn the waterway into a ''killing field for the aggressors.''

Reagan administration sources and published reports said a U.S. Navy F-14 jet fighter fired two missiles over the weekend at a suspected Iranian jet fighter that appeared to be making ''hostile moves'' toward a U.S. surveillance plane, but it did not appear that the missiles hit anything.

Iraq's warplanes bombed Iranian oil installations for the first time in nearly a month. Iraq said Iran had violated the U.N. Security Council's July 20 cease-fire resolution and deserved ''back-breaking, painful blows.''

The 247,347-ton Texaco Caribbean loaded a full cargo of oil at Iran's Larak Island terminal, said Lloyd's Shipping Intelligence in London. The tanker had passed out of the gulf through the Strait of Hormuz and was approaching an anchorage in the Gulf of Oman when it hit the mine.

Shipping sources and Texaco said the supertanker was holed about a yard below the water line and some oil was leaking, but no one was injured.

Italian television later reached the Texaco Caribbean by telephone and spoke to an unidentified Italian official on board, who said no one aboard was injured and the ship was not leaking any oil.

Some marine executives speculated that the mine drifted down from the strait, where Iran completed four days of naval maneuvers code-named ''Martyrdom'' on Friday, but a shipping official based in Kuwait said it probably was moored to the sea floor. He said coastal currents move toward Hormuz in this season rather than away from it.

Tehran radio suggested the United States was behind the mining.

Pentagon sources in Washington said the three Kuwaiti tankers and their Navy escorts were moving north - ''taking it slow and easy,'' as one put it - after anchoring overnight off Saudi Arabia, about 200 miles from Kuwait.

Brent Sadler of the British television network ITN said in a telephone report from a chartered boat, however, that the U.S.-Kuwaiti convoy had not moved by dusk.

Sources who monitor ship movements in the gulf said they could not confirm the convoy had sailed.

The convoy had stopped off the coast of Saudi Arabia Sunday night because a floating mine had been spotted in an area the ships were about to enter, Pentagon sources disclosed Monday.

The Reagan administration sources refused to be specific about when or where the incident involving the F-14 jet took place, but it was presumed to be near the gulf.

Navy jet fighters attached to the aircraft carrier Constellation, which is believed to be in the northern Arabian Sea, were already in the air when a Navy P-3 Orion surveillance plane said radar showed the approach of several airplanes, said the sources, who demanded anonymity.

Both The Washington Post and The New York Times reported in Tuesday's editions that an F-14 fired two Sparrow air-to-air missiles at the suspected Iranian aircraft.

None of the U.S. jets was harmed.

The Texaco Caribbean struck the mine about eight miles northeast of Fujairah, a port in the United Arab Emirates, and about 30 miles south of the Hormuz entrance. It anchored off Fujairah afterward.

It is owned by Lexington Tankships Ltd., a subsidiary of Texaco Panama Inc. At Texaco's headquarters in White Plains, N.Y., spokeswoman Anita Larsen would not confirm that the cargo was Iranian oil. The company said the tanker was under a ''single-voyage'' charter to the Norwegian shipping and trading company Seateam and ''under orders to proceed to northwestern Europe with a cargo belonging to that company.''

In Washington, State Department officials said current U.S. restrictions on transactions with Iran involve shipments of war materiel and dual-use items. They said they were unaware of any restriction on American tankers transporting Iranian oil.

This was the first known mining incident in the busy Gulf of Oman tanker anchorage. The U.S. Navy uses the area as an assembly point for convoys of Kuwaiti tankers sailing under the American flag.

Tehran radio, monitored in London, said Iran's naval maneuvers last week proved its ''total readiness'' to turn the gulf into a ''killing field for the aggressors.''

On Sunday, Prime Minister Hussein Musavi said: ''The Persian Gulf will remain full of mines and continue to be a dangerous region for ships.''

Hours before the Texaco Caribbean was damaged, a dhow struck a mine eight miles off Bahrain in the central Persian Gulf but no injuries were reported, shipping sources said. Dhows are slow wooden sailing vessels.

According to the sources, another mine was found Monday off Ras Khafji, an oil port 40 miles south al-Ahmadi, Kuwait's main oil terminal.

The U.S.-Kuwaiti convoy's overnight stop appeared to fit a Navy decision to make the most hazardous parts of the 550-mile voyage to Kuwait in daylight. The supertanker Bridgeton hit a mine on the first escorted trip up the gulf last month as the convoy passed a fortified Iranian island 120 miles from Kuwait.

Iran began making regular attacks last September on ships owned by or serving the emirate, which it accuses of receiving arms shipments for its eastern neighbor Iraq.

Eleven of Kuwait's 21 tankers are being registered as American vessels so Navy warships can protect them.

Iraq said its warplanes bombed a refinery in Iran's northwestern city of Tabriz and five oil fields in the western Khuzistan region.

Iran's official Islamic Republic News Agency said the raids damaged industrial complexes in Tabriz and at Gachsaran, an oil field south of the western Iranian city of Ahvaz. It said nine civilians were killed.