The Damascus-based group is not a member of the Palestine Liberation Organization.

The United States has long been concerned about the Damascus-based group, but that concern had been tempered by the group's quiescence in recent years.

Dr. Habash's Damascus-based group is the largest component of the P.L.O. after Mr. Arafat's own group, Al Fatah.

Ten Damascus-based Palestinian groups have called a general strike for Monday, when the P.L.O.'s peace agreement with Israel is to be signed in Washington.

The Damascus-based group had boycotted meetings of the P.L.O.'s cabinet since the signing in 1993 of interim peace accords with Israel.

He remained critical of the PLO leadership's stance and helped in the coordination of the Damascus-based Palestinian groups.

Political analysts said the Libyan decision meant that it was abandoning Mr. Arafat's remaining rivals, the four hard-line, Damascus-based groups that boycotted the session in Algiers.

Ten Damascus-based radical groups have called on all Palestinians to demand on Friday, through protests and demonstrations, the withdrawal of Palestinian negotiators from the peace process.

A radical Damascus-based group called the Palestinian National Liberation Organization claimed responsibility in a statement issued in Beirut, Lebanon.

He is not only protector of 10 Damascus-based radical Palestinian groups, but diplomats here also believe that he wields considerable influence over the Party of God guerrillas in Lebanon.