The administration has rejected a request from the U.S. military command in the Persian Gulf that American forces be allowed to extend their protection to non-American ships threatened by Iranian attacks, according to senior U.S. officials.

The query, which the officials asserted was put forth only informally, would have increased significantly the level of U.S. military activity in the gulf as well as the probability of clashes with Iranian forces.

"There's been no change in our policy," said White House spokesman Marlin Fitzwater. "U.S. forces are there to protect U.S.-flag ships and in some cases ships carrying U.S. military materiel."

"That would elevate military policy to another level," one Pentagon official said. "I don't think our military planners are prepared for that eventuality."

Fitzwater was reacting to a report in yesterday's Washington Post that Rear Adm. Harold J. Bernsen, commander of the Middle East Task Force, requested greater latitude to strike at Iranian gunboats attacking non-American ships in the gulf.

Administration sources said privately, however, that U.S. military commanders in the gulf have been raising questions about the ambiguities inherent in the current "rules of engagement," such as what action the command should take if it encounters "a ship in need" that is non-American or U.S.-owned but flying a Panamanian or Liberian flag, as many do.

In several recent instances, non-American ships have joined convoys of reflagged Kuwaiti tankers protected by U.S. warships, raising questions about what action, if any, the escorts should take if the other vessels are attacked.

"There are some in the military out there who have seen nonbelligerent ships being attacked, a ship in need, and asked 'What are we going to do?' " one official said.

To date, none of the non-American ships joining U.S.-escorted convoys has been attacked, however.

The U.S. gulf commands are also seeking clarification of the rules governing "hot pursuit" of Iranian speedboats caught in the act of attacking or laying mines in international waters, according to administration sources.

Three U.S. helicopters last Thursday night fired machine guns and rockets at four Iranian gunboats 15 miles southwest of Iran's Farsi Island after they were fired on. One gunboat was sunk, two were damaged and captured and a fourth escaped, military officials said. Six Iranian crewmen were rescued, two of whom have died from wounds. Tehran said at least six other crew members were killed.

Pentagon spokesman Fred S. Hoffman took issue with another Washington Post report yesterday that it was an armed gunship, and not an unarmed observation helicopter as the Pentagon first reported, that the Iranians had initially fired upon.

He said the Pentagon's initial reports on the incident were correct. But other Defense Department sources, who spoke on condition that they not be identified, continued to assert that all three aircraft were Army special operations MH6 helicopters, which are heavily armed.

U.S. military forces in the gulf have stepped up surveillance of Iranian activities and Pentagon officials have said they are authorized to attack any Iranian vessel found carrying mines or caught in the act of laying them in international waters.

But the question of U.S. policy toward Iranian speedboats or other vessels found engaging in hostile activities in international waters and seeking to flee back into Iranian territorial waters has apparently yet to be answered.

Both Fitzwater and State Department spokesman Charles E. Redman emphasized yesterday that the administration is not changing the current "rules of engagement" for the gulf task force which restricts U.S. military forces to protecting only U.S.-flagged ships and retaliating only when American vessels are in imminent threat of, or under, Iranian attack.

"The policymaking people are against it completely," said one U.S. official, referring to Bernsen's reported question about the possibility of extending American protection to non-U.S. vessels.

Administration spokesmen yesterday also indicated little willingness to press Iraq to stop its now almost-daily air attacks on Iranian oil tankers or Iran-bound vessels. The attacks have led to Iranian retaliation against neutral shipping and heightened tension throughout the gulf.

Redman, asked what the United States was doing to curtail the Iraqi attacks, said the administration had "urged restraint" on both sides and was "trying to do whatever we could to bring this war to an end."

Meanwhile, Rep. Les Aspin (D-Wis.), chairman of the House Armed Services Committee, yesterday said the administration should "lower our profile and hunker down" for an extended stay in the gulf.

"The heavy American presence in the region causes as many problems as it solves," he said. "It waves a red flag in front of the Iranian radicals."

Aspin called upon the administration to take advantage of any cease-fire, formal or informal, in the seven-year long Iran-Iraq war to end the policy of reflagging Kuwaiti oil tankers and providing U.S. military protection for them.

Staff writer Lou Cannon contributed to this report.