RIYADH, SAUDI ARABIA, SEPT. 2 -- Wielding the power of wealth, Saudi Arabia has become a key player alongside the United States in efforts to restrain Iraq's sudden escalation of air attacks in the Persian Gulf and force Iran to accept a U.N. cease-fire.

The Saudi campaign appears aimed at preventing hostilities in the gulf from exploding into a broader conflict that would involve the kingdom's own military forces, while at the same time concentrating international pressure on Iran to heed the U.N. Security Council's call for a halt to the fighting.

King Fahd, the Saudi monarch who handles much of the critical gulf diplomacy personally, conferred here yesterday with a top-level delegation dispatched by President Saddam Hussein of Iraq. The Iraqi group included Izzat Ibrahim and Saadoon Shakir of the ruling Revolutionary Council in Baghdad.

The outcome of their meeting was not disclosed, but Fahd a day earlier had expressed concern over the "noticeable escalation in the gulf," and emphasized his government's "wide counsel and moderation in all dealings," an announcement said.

This was interpreted as a signal to Saddam Hussein of Saudi displeasure over Iraqi bombing of Iranian oil facilities and tankers in the gulf, which resumed Saturday for the first time since the U.N. cease-fire resolution July 20. Diplomats said Fahd and Prince Saud Faisal, his foreign minister, have wanted Saddam Hussein to hold his fire to keep pressure focused on Iran while the cease-fire demand is pending.

Saud, son of the late King Faisal, has been pushing for the Security Council cease-fire resolution for some time, the diplomats said. He also was the driving force behind an Arab League decision last week in Tunis calling on Iran to accept the U.N. demand and threatening a break in relations if Tehran persists in its refusal.

As Fahd and Crown Prince Abdullah met with the visiting Iraqis, Saud conferred with the new U.S. ambassador here, Hume Horan. The content of their conversation was not disclosed, but diplomatic sources said the Reagan administration wants Saudi Arabia to join with the United States and other countries urging restraint on Saddam Hussein.

Direct U.S. entreaties with Saddam Hussein to stop the gulf air strikes have been rejected, reports from Washington said. Saudi Arabia, which has spent billions of dollars to support Iraq in the war, was expected to have greater influence in Baghdad than has the United States.

Iraq, which has been seeking a negotiated settlement to the seven-year-old conflict for some time, said it would accept the U.N. resolution on condition that Iran also did so. Since then, the Baghdad government has explained its resumed bombing as a way to force Iranian acceptance.

Ayatollah Ruhollah Khomeini's government in Tehran has yet to answer the U.N. call, insisting the resolution is faulty because it fails to condemn Iraq for starting the war with its attack on Iran. More broadly, Khomeini and other Iranian clerical rulers have said they will pursue the conflict until Saddam Hussein and his secular Baath Party have been toppled from power, in effect ruling out a negotiated settlement.

Despite the call for moderation, a Saudi source said Iraq has the right to attack Iranian oil shipments in the gulf because petroleum exports finance Iran's war effort. In addition, he said, Iran initiated the war against oil exports soon after the conflict began by hitting Iraqi facilities at the head of the gulf near Faw, destroying Iraqi ability to export oil by sea.

Iran's demand that the gulf shipping be excluded from the war also is seen here as an attempt to prevent Iraq from using its air superiority, confining the war to land battles, in which Iranian forces have the advantage, a diplomatic source said.

These viewpoints, part of an overall policy of support for Iraq against Iran, were expected to temper Saudi pressure on Saddam Hussein to stop the bombing. But Saud's diplomatic efforts, coupled with Saudi fears of a broadened conflict, have led to the desire for Iraqi restraint, diplomatic sources pointed out.

Concern has heightened as Iran begins to carry out its vow to retaliate for renewed Iraqi attacks in the gulf. The fears were emphasized yesterday, for instance, when Iranian Revolutionary Guards attacked a Spanish-flag oil tanker off Ras Tanura, site of a major Saudi loading facility on the shore of the kingdom's Eastern Province oil fields.

Saudi officials have expressed the belief that Kuwait would be the first likely target for any direct Iranian attacks on Iraq's Arab supporters and neighbors. Under commitments within the Gulf Cooperation Council, Saudi Arabia in principle would have obligations to help the neighboring country defend itself.

The council's secretary general, Abdullah Bishara, announced here yesterday that ministers of member states will hold a meeting Sept. 12 to review the tense gulf situation.

At home, Saudi officials have concluded the most likely threat from Iran is sabotage or terrorism, according to diplomats. Fahd warned Saudis yesterday to exercise particular vigilance, and Prince Mohammed, Fahd's son and governor of the sensitive Eastern Province, said Sunday that security has been tightened in that region's oil facilities.

The tone of Saudi complaints against Iran has mounted considerably since the Mecca violence July 30, which left hundreds of Iranian and other pilgrims dead and led to Iranian calls for the overthrow of the ruling house of Saud.

Although stemming from the Mecca killings, the toughened Saudi stance also has extended to the gulf, where U.S. ships are heavily involved in an effort to protect Kuwaiti oil shipments from Iranian attack. Fahd reiterated yesterday, for example, that if attacked, "we shall spare nothing in defense of our lands and everything we hold dear."

The Saudi military has been working closely with U.S. forces in the gulf, monitoring the waterway with U.S.-supplied AWACS surveillance planes and reportedly providing case-by-case landing rights for carrier-based U.S. planes. But Saudi and diplomatic sources said the kingdom has refused suggestions that a U.S. fighter wing be stationed at the Saudi Air Force's Dhahran base.

Basing the planes here would facilitate protection of U.S. ships in the gulf and, perhaps more important, provide a highly visible symbol of military cooperation for use by the administration in its dealings with Congress. A Saudi source said this would not be forthcoming, however, and contended that carrier-based U.S. planes in the Gulf of Oman can deal with the Iranian threat.