Police today arrested two members of a self-styled citizens' patrol group organized in the wake of the murders of 20 Atlanta children.

The group was established in a downtown public housing project, organizers said, to protect the youth of the neighborhood from the killer or killers who have been stalking the city's youth for nearly two years.

The arrests, which came as the group set out with rifles, pistols and baseball bats on its first patrol, climaxed a week of tension between police and organizers of the effort who claimed they had to defend themselves because of inadequate police protection.

Many Atlantans had feared the beginning of the patrol would mark a new wave of vigilatism in the troubled city, and police and reporters witnessing the inaugural patrol far outnumbered the 15 Techwood Homes housing project residents who turned out.

The spokesman for the patrol group, Chimurenga Jenga, was arrested as he emerged from the community center with an M1 rifle. Also arrested was a man identified as Gene Ferguson, who police said was carrying a handgun. Ferguson offered no resistance, but Jenga had to be dragged from the scene by police.

Alanta Deputy Police Chief Edrin Bell, who coordinated the operations of some 25 officers on the scene, said both men would be charged with carrying a firearm at a public gathering, a misdemeanor. Jenga claimed before he was taken away that all the group's firearms were unloaded.

Police maintained all week that they did not want a confrontation with the Techwood Homes group.Public Safety Commissioner Lee P. Brown declared Thursday night, "We will not be placed in an adversary relationship with our citizens." Since the formation of the patrol was announced last Sunday, police insisted that some accommodation would be made.

However, Jenga was equally insistent that the patrols would begin and that patrol members would be armed.

None of the 20 dead and missing Atlanta children were from the Techwood Homes area. Jenga said before the launching of the patrol that its purpose was "to make sure that it doesn't happen here."

"We are not vigilantes," Jenga said. "Our mission will be no different from that of any mother or father who watches their children play." But as the group prepared to emerge, police distributed a statement listing a number of offenses for which the group might be subject to arrest. A last-minute meeting between Bell and the group failed to forestall the start of the patrol.