The ornate iron gates of Washington's Islamic Center on Massachusetts Avenue have been locked for the last month. Instead of Arabic invocations, silence fills the Mecca-facing masjid, or prayer room, beneath its minaret. Out front, the banners of a small band of protesters call the center's closing an affront to religious freedom.

This has been the scene since March 5, when District police blocked the entrance of the mosque at the request of its owners, the 29 ambassadors from Islamic countries serving in Washington, and prevented about 100 chanting Moslem worshipers from entering for their prayer services.

That event was the latest turn in a bitter internal feud that has made the beautiful 35-year-old landmark along Washington's elegant Embassy Row a place of intrigue, confrontation and bickering for three years.

Both sides portray the controversy as a legal tussle over the control of a religious establishment and the method of choosing its spiritual leader or imam. But long interviews with participants on both sides reveal there is more at stake here.

In fact, the mosque has become a local stage for tensions seething beneath the surface in the Islamic world and chipping at the political status quo in several Middle Eastern countries with close ties to the U.S. In addition, the controversy highlights the changing nature of Washington's own Islamic community, which was mainly a diplomatic one when the center opened its doors in 1957.

The Islamic ambassadors who built the center, with the encouragement of builder A. Joseph Howar, a Palestinian immigrant who was one of the first Moslems to settle in this area in 1903, intended that it should provide a mosque for prayers and a library and bookshop to educate the public about Islam.

Howar became the only American and only nondiplomat on the board of governors, a slot his son Edmond took over when he died. The board appoints the center's administrator and imam, usually someone esteemed for his scholarly credentials in Islamic studies. Each member-country on the board makes voluntary contributions to the annual budget of the center, which now runs about $450,000 a year.

Since the center's opening, the number of Moslems in Washington has grown enormously--to a total estimated now between 20,000 and 50,000--because of increasing numbers of immigrants and increasing numbers of Americans, both black and white, who are converting to Islam.

American Moslems are found on both sides of the current conflict at the mosque.

Some of the congregation now are disputing the board's right to appoint the center's staff. "During the 30 years the Islamic community came into existence and Islam is flourishing in D.C. and it's not just the diplomatic community as it used to be," said Mohammad Asi, who was chosen imam by the dissident faction at the mosque.

"Moslems asked for participation in the Islamic Center, they asked for more say. This did not go down well with the ambassadors," said 31-year-old Asi, who was born in Michigan and has been in Washington nine years.

Cherif Sedky, a lawyer who represents the board, said its position is that as the owner of the mosque it has the right to run it as it wishes. The board feels "that this is simply a question of people defying the board's authority to run the center in the manner they have the responsibility and authority to do," Sedky said.

At the core of the dispute, however, is a conflict between two different visions of Islam in the modern world.

One vision, held by the Western-educated elite of Islamic countries that would include most of the center's ambassadorial board members, accommodates some of the political concepts and secular goals of Western thought.

The other version of Islam is a fundamentalist, back-to-basics one that has sprung up in many Islamic countries, often as a dissident political movement.

An example most familiar to Americans is Iran's government-by-clergy, where politics and religion are indistinguishable.

At the Islamic Center, the back-to-basics kind of Islam is held by Asi's small but active group, which is governed by an elected 10-member "Council of Guidance."

It comprises both Americans and foreigners.

Though he is not spoken of by the group as a leader and does not claim that position for himself, one of the most active in the group is Bahram Nahidian, a naturalized American of Iranian descent who is a member of the "Council of Guidance."

Asi's group regards the ambassadors on the board as munafiqs, an Arabic word meaning "deviators" or "hypocrites" who have allegedly strayed from the true Islamic way. The literature of the group accuses the ambassadors of representing "so-called" Moslem countries whose governments, they contend, do represent neither the Moslem peoples of the East nor the Moslem community in Washington.

One of the ambassadors most criticized in their literature and statements is Saudi Arabian emissary, Sheikh Faisal Alhegelan. "He wishes the center to be a place to bring his own politics and not true Islam. His policy is not to let Islam be promoted according to the Koran and traditions of the Prophet. His view is to follow the Western pattern," said Nahidian.

Ambassador Alhegelan did not comment on the allegations.

Asked to name other "un-Islamic" actvities by the Moslem ambassadors, their critics have complained that some serve alcoholic beverages at their parties and do not attend prayers at the mosque.

Problems first began at the mosque around the time of the Camp David Accords in 1978, which were widely criticized in the Islamic world.

At this time the imam was an Egyptian named Abdul Rauf, who kept political discussions to a minimum at prayer services in accordance with the wishes of the board, whose members often did not see eye-to-eye on political issues and sometimes were literally at war over them, sources on the board said.

Asi said his followers "wanted a more dynamic administration which would address these issues and which would not just be the rubber stamp of the ambassadors and legitimize everything they did."

Those followers criticized Rauf for not taking a stand on the Camp David Accords during the prayer services. Other topics this faction wanted addressed were "the Islamic revolution in Iran; the invasion of Afghanistan; the revolutions in Syria and Iraq and the persecution of Moslems throughout the Moslem realm," according to Asi.

When the Iranian revolution came along the activities of the group increased. Most of those who support the board's position say that at this point they came to believe that Asi's faction wanted to take over the center to provide a platform in Washington for the religious and political views of the Islamic revolution in Iran.

"The situation has turned into a continuous battle between Iran and other Islamic countries of the region . . . , " said Mostafa Abulghaith, a former acting director of the center. "While they see it as religious undertaking many other people see it as a geopolitical power-struggle that has nothing to do with religion.

"They want to be supreme, the primary voice in Islamic religious centers in Europe and the U.S.," Abulghaith said.

Leaders of the dissidents say that although they sympathize with the Islamic revolution in Iran, they are not promoting the interests of that country.

According to most sources familiar with the center, there are a large number of Iranians among the foreign members of the dissident group. Nahidian, a Georgetown Persian carpet dealer, has been one of the most vocal supporters of Iran's Islamic revolution.

Rauf resigned and was replaced in August 1980 by Muzammil Siddiqi, an Indian, who had an even harder time with the dissident faction. Twice, said Siddiqi in a telephone interview from Garden Grove, Calif., the situation almost came to blows as some of his opponents shoved and pushed him in the mosque.

Though he appreciates the groups' concerns about backsliding from Moslem practices, Siddiqi said he could not agree with their politicization of the mosque. "My own feeling is that there are lots of things happening in the Islamic countries which do not fully represent Islam . . . but to take the control away from the ambassadors , there is no need for it. Why focus on this center?" said Siddiqi.

The former imam said he did not like giving the center "a kind of political image . . . . I felt you could criticize these governments in their politics but not at prayer time."

Unable to carry out his duties as he wanted, Siddiqi quit in September 1981. The following month the board of governors announced the center would be temporarily closed for repairs. A move by the dissidents to block the closing in D.C. Superior Court failed. In December 1981, Superior Court Judge Robert A. Shuker confirmed the board's contention that it alone was the rightful owner and operator of the mosque.

In early 1982, the dissidents stepped up their attempts to take over the daily affairs of the mosque, according to Sedky. Asi moved into the imam's official residence, some of the dissidents hung around the center's offices all day and harassed the employes, finally ordering them to leave the center, according to Sedky.

Asi said the former imams and staff were "phased out" and left because they recognized they were "unpopular."

Meanwhile, attendance dropped off at the center, whose congregation is mainly immigrant professionals and business people who normally attend Friday services during their lunch hours and then hurry back to work, avoiding confrontation with the more activist group, Siddiqi said.

After attempts to negotiate a compromise with the dissidents failed, the board took control of the center on March 5. Accompanied by a locksmith and security guard and backed up by District police standing nearby, Sedky went to the center and asked Asi to leave or face arrest. After Asi's departure, police made a two-hour search of the center for weapons but found none, Sedky said.

Many area Moslems fear the controversy at the mosque will reflect badly on Moslems in general. The dissidents "must not say they are doing it for the sake of Islam. The net effect of what they are doing has been a disservice and harmful to the Islamic community in the U.S. because it projects the wrong image of what Moslems are. It has confirmed the fears of many people that Moslems are confrontational and preparing for some kind of holy war. And this is not true,"said Abulghaith.

Nahidian says he and the dissident group cannot simply attend another mosque, since by Islamic law they must worship in the "main" mosque of the city they live in.

His opponents disagree and contend the group wants control of the center because it is well-known, strategically located and, as the property of the Islamic ambassadors, has high international visibility. "When they hang a banner there they can be sure it will be seen by thousands of commuters," said one Moslem who used to work at the mosque.

There is now a delicate standoff at the center and the prospects of a compromise seem remote. The board announced the center would remain closed "for public safety" until "the demonstrations cease."

"The board of governors feels they have for almost two years tried their damnedest best to reason it out with them . . . and the possibility of rapprochment seems to be rather difficult if not impossible because one group is munafiq," said one Moslem diplomat involved in the conflict.

"If they are willing to have the principles of the Koran as the basis of discussion , we're willing to sit down. But if they want concessions or negotiations from a power position, we are not interested," said Asi.