KUWAIT, AUG. 7 -- Iran today completed its four-day "Martyrdom" naval exercises in the Strait of Hormuz with the test firing of an unidentified shore-to-ship missile and the ramming of a speedboat loaded with explosives into a dummy "enemy target," according to official Iranian accounts.

Iranian President Ali Khamenei, standing on the deck of a command ship at the port of Bandar Abbas on the strait, watched Iranian Navy vessels and hundreds of speedboats pass in review with their crews chanting, "The Persian Gulf is the burial place of {President} Reagan," according to Tehran radio.

The maneuvers, which had caused fears in world capitals that Iran might close the narrow strait at the opening of the Persian Gulf, ended as Pentagon sources, according to reports from Washington, said the escorting of reflagged Kuwaiti tankers has been "postponed indefinitely" while the U.S. Navy reassesses its capabilities to meet mine, terrorist and other threats in the volatile gulf region.

Commercial shippers have rushed their vessels in and out of the gulf in the past few days in anticipation of the next American convoy, The Associated Press reported today.

Ship traffic exceeded normal averages by 20 percent in a 24-hour period from Wednesday to Thursday, a shipping executive said. Some ship owners said they are avoiding the U.S. escort because it raises the specter of a U.S.-Iranian confrontation.

Three tankers and their U.S. Navy escorts had been expected to sail from their anchorage in the Gulf of Oman late this week. But Pentagon sources in Washington said today the Navy is likely to begin the next escort sometime late next week after its force of mine-sweeping Sea Stallion helicopters has been positioned to help protect the convoys.

The Italian government today asked the United Nations Security Council to consider organizing a mine-sweeping operation in the gulf, officials in Rome said.

Pentagon sources in Washington said the Navy was extremely embarrassed by the mine explosion that holed the reflagged tanker Bridgeton on the first U.S. escorting mission.

The Navy is attempting to prepare contingencies against other threats, such as suicide speedboats, the sources said.

The helicopter carrier USS Guadalcanal today began steaming toward the Persian Gulf from the British island of Diego Garcia in the Indian Ocean, where it picked up eight U.S. Sea Stallions, according to the Pentagon sources.

The transport will become the 10th U.S. warship assigned to patrol within the Persian Gulf.

{A West German Defense Ministry spokesman said the Bonn government may send a small naval detachment to the North Atlantic or the Mediterranean to free up U.S. ships for gulf duty, the AP reported.}

Tehran radio said the shore-to-ship missile was test-fired on the Strait of Hormuz on the orders of President Khamenei. The radio did not say what type of missile was fired. Iran has deployed Silkworm antiship missiles along the shore of the 44-mile-wide strait. The Chinese-made missiles are capable of hitting targets 50 miles away.

Iran's official IRNA news agency said the explosives-packed speedboat was rammed by remote control into a "hypothetical enemy target" in the gulf. It did not reveal the location.

Meanwhile, in Tehran, tens of thousands of mourners staged a mass burial for about 50 Iranian pilgrims killed during clashes with Saudi police at the holy city of Mecca last Friday, Tehran radio said.

The Saudis have said 402 people, including 275 Iranians, were killed in a stampede; Iran has claimed that more than 600 Iranians died when Saudi police opened fire on them.

After parading many of the corpses at Friday prayers at Tehran University, the mourners buried their dead at the Behesht Zahra cemetery that contains the graves of thousands of soldiers killed in Iran's seven-year war with Iraq.

Iranian leaders again blamed the United States for the violence at Mecca.

At the funeral, Interior Minister Ali Akbar Mohtashemi vowed that the Mecca massacre would not go unpunished, according to Tehran radio.

Iran "will not allow the shameful and tragic acts of the Saudi police and regime to go unanswered, although the direct responsibility lies on the shoulders of America, which issued the order," he said.

"We will take our revenge on America directly," he said.

Iranian Chief Justice Abdulkarim Mousavi Ardebili, at the earlier prayer session, declared that the U.S. Navy's gulf buildup had failed in its intent to frighten Iran, according to Tehran radio. "Once we could not sleep for fear of America, now America cannot sleep for fear of our basiji {volunteers}," he said.

The end of the Iranian naval maneuvers brought a collective sigh of relief from oil and shipping sources in the gulf who had feared that the exercises might result in the closing of the Strait of Hormuz, through which about 17 percent of the world's energy resources flow, according to a study by the Paris-based International Energy Agency.

The fact that, for all its fiery rhetoric, Iran did not seek to close the strait during the maneuvers was taken here by shipping sources as a reassuring sign that ultimately Iran would not take such a step, because it would hurt its own oil shipments as well as that of the other gulf nations. Washington Post staff writer Molly Moore contributed to this report from Washington.