Iran fired two missiles into a residential neighborhood of the Iraqi capital of Baghdad overnight, killing "many people," hours after Iraqi warplanes attacked several Iranian oil facilities in the Persian Gulf, damaging the world's largest supertanker, according to reports from the region.

Tehran radio said the first missile struck Baghdad at 10:07 p.m. local time and hit a military training center. Residents said they could hear the explosion over a wide area of Baghdad, Reuter news agency reported.

A second missile struck a residential area of Baghdad about 12:25 a.m. today, killing and wounding civilians, the official Iraqi news agency said, quoting an Iraqi military spokesman. The report was monitored in London.

Iranian officials said the attack was in retaliation for Iraqi air raids on Iranian cities and industrial targets, according to the official Iranian news agency IRNA.

Iraqi authorities did not release any casualty figures, saying only that "many people" died and that houses and shops were damaged.

War communiques from Baghdad said the air raids against Iranian oil terminals on the northern and southern ends of the gulf were launched yesterday in response to Iranian shelling Sunday of four Iraqi border cities. Iraqi officials reported that 31 civilians were killed and 51 wounded in the barrages.

The attacks and counterattacks represent yet another escalation in the seven-year-old war between Iraq and Iran. Iran struck Baghdad with about 24 Russian-made surface-to-surface missiles last year and early this year, but had not fired one into the city since mid-February, The Associated Press reported. In addition, Pentagon sources said they believe that Iran is preparing for a major ground attack against Iraq this fall.

Meanwhile, two Italian warships escorted an Italian-flagged commercial vessel into the gulf yesterday in the first naval convoy that Italy has provided to protect its merchant shipping in the waterway, United Press International reported.

News agencies also said that a convoy of nine Japanese-flagged or Japanese-crewed tankers left the gulf yesterday after their owners and a Japanese maritime union ordered the vessels out of the region.

In yesterday's air raids, Iraqi warplanes hit the 564,739-ton tanker Seawise Giant, the largest supertanker, and four other tankers at the makeshift Larak Island oil terminal in the Strait of Hormuz, the narrow passageway leading into the southern end of the gulf.

The Seawise Giant, which is operated by a Hong Kong company, was being used for storage. It was only slightly damaged, shipping sources in the region said, but 15 tugboats were fighting fires on one of the other vessels, the Cypriot-flagged products carrier Shining Star.

The other damaged vessels included tankers registered in Liberia and Panama and a second Cypriot-registered ship. One sailor was reported slightly injured.

Iraq said its French-built F1 Mirage fighter planes flew 600 miles south to raid the Larak terminal and another on nearby Lavan Island, according to reports from the region. Although Iraqi officials say their Air Force has attacked 21 ships in Iranian waters since late August, their fighters seldom make the long flight to hit terminals as far away as the Strait of Hormuz.

Iraqi jets also launched "destructive strikes" on the Iranian Cyrus oil field in the northern gulf, leaving the site "mere rubble, engulfed by flames," according to Baghdad radio. Iraqi forces also reportedly attacked Farsi Island, site of Iranian oil facilities as well as a base for Iranian Revolutionary Guards who have launched speedboat attacks against nearby shipping.

Meanwhile, U.S. military forces continued their search yesterday for the pilot of a Marine helicopter that crashed in the Persian Gulf Sunday night.

Three Marine crew members were rescued after the UH1 utility helicopter crashed about 900 yards from the U.S. Middle East Task Force flagship USS LaSalle.

Rear Adm. Harold J. Bernsen, task force commander, said the copter's crew lost control after the aircraft began vibrating. Bernsen, interviewed by reporters in Bahrain, said Sea Stallion mine-hunting helicopters from the assault carrier USS Guadalcanal would use sonar gear to locate the wreckage of the helicopter that would then be salvaged.

It was the second crash of a U.S. helicopter in the Persian Gulf in the past three months. Four Americans were killed when a SH3G Sea King crashed July 31 while trying to land on the LaSalle.

Pentagon officials identified the missing pilot as Maj. Daniel S. Haworth, 34, of New Castle, Del.

The three crew members who were rescued and listed in good condition were 1st Lt. Robert M. Melzer, 26, of Laurel, Md.; Cpl. Michael D. Gauthier, 21, of Hampton County, Mass., and Lance Cpl. Gregory M. Bentley, 20, of Douglas, Ga. All were based on the Guadalcanal and assigned to the Marine Medium Helicopter Squadron 263 in Jacksonville, N.C., Pentagon officials said.

Melzer's mother, Marilyn E. Melzer of Laurel, said she talked to her son by telephone yesterday. He said he was "fine and well" and was not injured, she said. She said her son, who has been assigned to the Persian Gulf for the past five months, was "praying" for his friend Haworth, the missing pilot.

Washington Post staff writer Retha Hill contributed to this report.