IN a small, dingy office in downtown Nablus, two intense young Palestinians, anonymous members of the shadowy ``Guardians of the Uprising,'' tell of efforts to prevent the 29-month Palestinian uprising from turning against itself. Part of a network formed six months ago by the city's uprising leadership, the youths have become a kind of neighborhood ``watch committee.'' Their mission is to help stop a wave of inter-Arab violence that, since the start of the uprising, has torn at the fabric of Palestinian unity.
In theory, the casualties have been from Palestinians who have collaborated with the Israeli occupation authorities. In fact, the uprising increasingly has been used to justify criminal activity or to settle old family or factional feuds.
``People have been exploiting the uprising,'' says one of the Guardians, a haggard, bearded 26-year-old.
Using tactics ranging from gentle persuasion to lethal force, the Guardians are one reason that the killing of Palestinians by other Palestinians has virtually ceased in Nablus since the start of the year. But elsewhere in the West Bank and Gaza, internecine violence continues.
``There's no indication yet that the problem is being controlled,'' says Lt. Col. Moshe Fogel, a spokesman for the Israeli Defense Forces (IDF).
Leaflets issued by the leadership of the Palestinian uprising now call for an end to the killings altogether, but many Palestinians privately say that, with no government and thus no prisons, no alternative exists to deal with Palestinians regarded as traitors.
Since the start of the uprising in December 1987, more than 210 Arabs have been killed by other Arabs, most since the early in 1989.
The killings have sapped the strength of the revolt against Israeli rule in the occupied West Bank and Gaza Strip. Israeli leaders, meanwhile, have pointed to the sometimes-brutal slayings to bolster their argument that Palestinians are not ready for independence - or ready even to participate in serious bargaining over the future status of the territories.
Israeli sources attribute the dramatic increase of inter-Arab violence to the strengthening of enforcement arms of the uprising, known as the ``strike forces'' or ``Popular Army,'' which ensure compliance with boycotts and strike decrees handed down by the uprising leadership.
Palestinians attribute the increase to an Israeli offensive launched in May 1989, which combined a peace plan with aggressive military countermeasures, which included reactivating a network of Palestinian informers to report to Israeli security.
Whatever the reason, Palestinians now concede that the campaign to bring Palestinian quislings to justice quickly provided a pretext to settle old scores, to avenge family feuds, and even to punish those accused of disreputable behavior.
``It quickly turned to excess,'' concedes a Palestinian source, who asked not to be identified. ``Collaborators became prostitutes and vice versa. We allowed ourselves to be carried away.''
``Once you legitimize the right to murder it becomes very difficult to stop,'' Colonel Fogel says. ``They have lost control of the situation.''
Daunted by bad publicity and fears of repeating the infighting that doomed the Arab revolt of the 1930s, Palestinians are seeking ways to impose stricter discipline.
The main Palestine Liberation Organization (PLO) factions in Nablus have agreed on strict criteria for the death penalty: having killed other Palestinians, having sold Arab land to Israelis, or having recruited Arabs to cooperate with Israeli authorities.
The enforcement mechanism of choice has been social isolation. In one recent instance, the Guardians of the Uprising held an entire family living in Nablus's casbah district under house arrest for six months until a family member, accused of being a collaborator, ``repented.''
When such techniques fail, Guardian members have resorted to sterner measures. Three months ago public beatings were administered to four youths who, without authorization, attacked Palestinians that they had mistaken as collaborators.
In extreme cases, the ultimate punishment - the death penalty - is meted out, but no longer in public settings.
``It has do be done humanely,'' says the spokesman for the Guardians, whose operations have recently expanded to the West Bank town of Ramallah.
One Palestinian, shot to death for being a collaborator, turned out to be the victim of mistaken identity. He was later declared a ``martyr,'' the highest accolade bestowed by the uprising.
Inroads on free-lance violence in Nablus have also stemmed from an almost unprecedented coincidence of interest between the PLO and the IDF in curbing the excesses of two gangs accused of killing at least 25 Palestinians.
Operating freely in the Nablus casbah, the Black Panthers and Red Eagles used M-16 rifles, pistols, and even Uzi submachine guns captured from Israel to kill randomly and often, challenging the control of both the PLO and Israel. After the Army broke up the groups in raids late last year, the PLO moved quickly to ensure that they did not reemerge.
``If people have weapons and don't obey, that's a problem - especially when they act in your name,'' says a leading West Bank journalist of the stakes involved for the PLO. ``As for the Israelis, they understood that if the Panthers weren't stopped, the day would come when such weapons would be used against them.''
Inter-Arab violence has been highest in areas, like Gaza, where high unemployment has increased criminal activity and where low social cohesion has made deterrence difficult.
Following an amnesty period after the start of the uprising, leaflets issued by the local uprising leadership urged Palestinians to pursue collaborators. Leaflets last fall began urging caution before inflicting capital punishment, then dropped references to collaborators altogether.
``In many cases, fellow Palestinians who are collaborators are the only enemy they have access to,'' says a Western development official in the West Bank, explaining why inter-Arab violence is not likely to be completely contained.