Outside, the not-too-distant rattle of gunfire suddenly punctuated the muezzin's droning call to noon prayers from an adjacent mosque, but in his ramshackle West Beirut office Nabih Berri did not even look toward the window.

As the leader of Amal, the newly reinforced militia arm of Lebanon's Shiite community, Berri was explaining that his was very much a Lebanese movement. It does not answer to any of the neighboring regional governments or powers that for so long have used Lebanon as an arena for their own vicious proxy wars, he said.

Berri's arguments were complicated by the fact that in the past months Amal has emerged as a new major force among Lebanon's Moslems and increasingly has been fighting pro-Iraqi groups among the Palestinians and Lebanese leftists. It is also obvious that one of Baghdad's biggest headaches these days is Iran's Ayatollah Ruhollah Khomeini, whose Islamic revolution has reverberated in Shiite consciousnesses throughout the Arab world.

In the last two weeks Amal has been accused by Iraqi-controlled media of having been behind the assassination of two prominent Lebanese with ties to Baghdad: Musa Shaib, a member of the regional leadership of the pro-Iraqi wing of the Baath Party and Riyad Taha, the head of the Lebanese Publishers' Association who recently had visited Baghdad.

Following those killings, Amal militia clashed violently with local pro-Iraqi groups, including the Palestinian Arab Liberation Front. In the lastest clash last week, the Iraqi Embassy was damaged seriously by Amal shells. An Amal-supported hospital near the Iranian Embassy also was damaged.

Berri denies that his men are doing the bidding of any outside force, be it Khomeini's Islamic republic in Iran or President Hafez Assad's Syria, another of Baghdad's antagonists.

"We are representing no one but the Lebanese and do not have anything to do with anyone who does not have Lebanese roots," Berri said. "We are not a movement of assassins but aiming at preventing the assassination of the Lebanese south."

Amal is deeply rooted in southern Lebanon, where a large part of the country's 950,000 Shiites come from. Found six years ago by the community's religious leader, the Iranian-born Imam Musa Sadr, Amal aims at supporting the Shiites, who are frequently caught in the cross fire between the Palestinians in the south and the Israelis who repeatedly attack the Palestinian camps.

Its other purpose is to give greater clout to the Shiite community as a whole. Although the Shiites make up one of the largest religious communities in Lebanon, they have long been relegated to secondary politicals roles. The presidency of Lebanon is reserved for a Maronite Christian and the prime ministership for a Sunni Moslem, but the highest a Shiite politician can aspire is to become speaker of the Lebanese parliament.

Amal languished in relative insignificance long past Musa Sadr's still-unexplained disappearance two years ago while on a trip to Libya.

Diplomats report, however, that Amal recently has benefited from Syrian arms and money, making it for the first time a serious military and political factor. It has clashed with Palestinian groups in southern Lebanon as well as with the Iraqi groups in and around Beirut.

Berri insists that the northern clashes have been forced on Amal by the Iraqis, who were angered because his group has "good relations" with Syria and because it had criticized Baghdad for its recent execution of the Iraqi Shiite leader, Mohammed Bagher Sadr, earlier this year.

"Certain Arab regimes want to err in their countries and then pay the price of their mistakes in Lebanon," says Berri, 43, a lawyer whose wife and six children now live with relatives in Michigan. "They get pregnant elsewhere and then want to deliver [their babies] on Lebanese soil. We Lebanese can no longer tolerate that."

For all that, Berri does not deny receiving a certain inspiration from Khomeini, who reticence to meddle in other nations' affairs has yet to manifest itself. However, whether there is some sort of "Shiite international" based in Tehran, as the Iraqis insist, is difficult to prove. Berri denies any such connection.

"We were founded six years ago, before the Iranian revolution surfaced," Berri says. "I don't think Iran really needs Amal to fight the Iraqis."

The Iranian revolution, however, has clearly cast its shadow on the struggle of Lebanon's Shiites.

"We have learned many lessons from the Iranian revolution, among them that reason is stronger than arms, and the word is stronger than the bomb, and religion has its own revolutionary impact," the Amal leader said. "I think we discovered that religion is not the opiate of the people as the communists says.

"The Iranian revolution has helped us a great deal in that it has shown us that the weak and the deprived can fight and do have strength if they are united."

Outside, the gunfire had died away and been replaced by the roar of taxicabs up the Corniche Mazra. Lebanon was back to normal.

"We don't want to be fighters," Berri said, "We have taken up guns to defend the integrity of our country. Once that is done, I look forward to belonging to nothing more than the Lebanese Bar Association.