KUWAIT, AUG. 10 -- Military tensions escalated further in the Persian Gulf today as Iraqi warplanes bombed oil installations deep inside Iran for the first time in several weeks, while a U.S.-chartered supertanker loaded with Iranian oil struck a mine just outside the gulf.

Inside the gulf, a U.S. Navy convoy escorting reflagged Kuwaiti tankers was slowed by evidence of other underwater mines in its path as it prepared to enter a particularly dangerous stretch of water near the spot where the supertanker Bridgeton struck a mine last month.

In Washington, Pentagon spokesman Robert B. Sims said the convoy has "paused, it has stopped, it has varied course and speed . . . to take care of operational concerns we have."

The incidents dealt at least a temporary setback to hopes here that the growing U.S. military buildup to defend free navigation in the Persian Gulf would diminish the threat of a widening of the 7-year-old Iran-Iraq war to include the moderate Arab states that ring the gulf's southwestern shores.

While the renewed evidence of apparently Iranian-placed mines in the gulf caused consternation here, the new Iraqi air raids against Iranian oil facilities were being interpreted as an even greater danger.

The attacks raised immediate fears in this vulnerable, strategic emirate that Iran might make good its threats to retaliate for such raids by striking back at Kuwait's oil facilities or at the reflagged Kuwaiti oil tankers and their U.S. Navy escorts.

"That Iraq has begun to attack Iran's oil facilities again is real bad news," said one western diplomat here, asking that he not be named. "We had hoped they would not do so anymore to encourage Iran to consider a cease-fire."

The Iraqi attacks were the first since the July 20 United Nations Security Council resolution calling for a cease-fire between Iran and Iraq. Under pressure from the United States and the U.N. Security Council members, Iraq was prevailed upon to suspend its air attacks on Iran and Iranian shipping in the gulf at that time.

Apparently under U.S. pressure, Iraq already had decreased its air attacks against Iran since the May 17 attack by an Iraqi warplane on the USS Stark that killed 37 American sailors. Iraq said that the attack was an accident.

Gulf shipping sources reported this afternoon that the U.S.-operated, Panama-registered supertanker Texaco Caribbean, a 117,200-ton vessel, had been damaged by a mine as it sought to anchor off the United Arab Emirates port of Fujayrah, on the Gulf of Oman, about 80 miles south of the entrance to the Persian Gulf. Many tankers use Fujayrah as a resupply station.

This was the sixth tanker to have struck a mine in the past three months, but the first one to do so outside the Persian Gulf, including the Strait of Hormuz. This raised fears that mines may be drifting out of the Persian Gulf into other crowded shipping lanes.

It is off Fujayrah and the port of Khor Fakkan just to the north that ships have been gathering to stage runs into the Persian Gulf, where in the past three years about 300 ships have been damaged by air, sea and, more recently, mine attacks.

Ironically, the Texaco Caribbean was damaged after having picked up a full load of Iranian crude from Iran's oil loading facility on Larak Island, just inside the Strait of Hormuz.

Despite years of confrontation with Iran, the United States still buys about $500 million in crude oil from that country.

The Texaco Caribbean had a four-yard-wide hole blown just below the waterline and was leaking oil, but no casualities were reported.

It is not clear whether the mine was floating or below the surface or if it had drifted out of the gulf. Pentagon officials said they were uncertain which nation may have placed the mine that struck the vessel.

Iran is believed to have done most, if not all, of the mining inside the Persian Gulf, although Iranian officials also claim that Iraq has laid some mines. U.S. Defense Secretary Caspar W. Weinberger yesterday said mines previously found outside Kuwait harbor and in the area where the Bridgeton was damaged were of the type that Iran possesses.

Iran always has been hurt more by the so-called "tanker war" in the gulf than has been Iraq. Iraq sends most of its oil exports through pipelines in Saudi Arabia and Turkey, while Iran is forced to move its revenue-producing oil in ships through the gulf. Iraq began the tanker war in 1984 by striking at Iranian vessels as a way to get at Tehran's economic lifeline when Iraqi forces found themselves pressed in the ground war by the Iranians.

According to Iraqi war communiques, the Iraqi Air Force today struck at Iran's refinery at Tabriz and five other oil installations in central and southern Iran.

Iraq said it resumed its raids because of Iran's refusal to accept the 10-point U.N. Security Council resolution that had sought to get both sides to cease military activities and to negotiate an end to the war that has been the longest, costliest and bloodiest in recent Middle East history.

A month ago, Iran warned that if Iraq persisted in attacking tankers carrying its oil through the gulf or striking at Iranian oil facilities, then Iran would retalitate not only against Iraq but also Kuwait.

Iran has singled out Kuwait for retaliation because of the cash subsidies, port facilities and air space that it has provided Iraq during the war. Kuwait is especially vulnerable, situated as it is just south of Iraq at the northern end of the gulf.

Iranian threats against Kuwaiti shipping this year led the Reagan administration to agree to raise the Stars and Stripes over 11 Kuwait-registered oil tankers and liquefied gas carriers and to provide them with U.S. Navy escorts.

The limits of U.S. protection of Kuwaiti shipping, however, were demonstrated again when the second convoy to run the Iranian gantlet up the gulf from the narrow Strait of Hormuz was forced to halt its 550-mile journey to Kuwait last night.

According to gulf shipping sources, the convoy was halted off the Saudi Arabian oil terminal of Ras Tannurah after Navy helicopter crewmen flying in front of it thought they spotted a mine in a shipping channel south of Farsi Island, a known base of Iranian Revolutionary Guards.

It was in that deep-water channel that the Bridgeton was damaged by a mine July 24 during the U.S. Navy's first convoy to Kuwait.

Shipping sources tonight said the convoy was expected to remain halted off Ras Tannurah until Tuesday morning to allow Navy mine-hunting teams to clear any mines that can be spotted.

While the Seasprite and Seahawk helicopters based on the Navy escort ships are able to hunt for mines, they are not able to carry out mine-sweeping operations, according to Pentagon officials.

Pentagon officials have said some Persian Gulf nations are helping in the mine-sweeping operations, but they have refused to elaborate.

A real U.S. mine-sweeping capability will not be in the area until later this week when the helicopter carrier Guadalcanal is expected to arrive with eight Sea Stallions specially rigged for mine detection and clearing.

The U.S. Navy was caught by surprise by the mines when it began its convoys, despite the fact that at least four ships had been holed by them this year in the vicinity of Kuwait.

Despite the mines and renewed fear of air attacks, shipping sources here said shipping traffic was continuing relatively undisturbed, even into Kuwait, whose oil and gas delivery schedules are reportedly being met.

According to Pentagon sources, the latest escorting operation through the Strait of Hormuz, where U.S. intelligence sources have identified antiship Silkworm missile launching sites along the Iranian coastline, included for the first time an AEGIS cruiser, the USS Valley Forge, the Navy's most sophisticated air defense ship.

The use of the Valley Forge, deployed from the aircraft carrier group stationed in the north Arabian Sea, is another in the growing list of powerful military assets being used by the United States in its gulf escorting operation.

Staff writer Molly Moore contributed to this report from Washington.