The Popular Revolutionary Bloc accepted Panamanian asylum today for 25 of its members occupying the French and Venezuelan embassies in the Salvadoran capital and said it would release all hostages, including French Ambasador Michel Dondeene.

The agreements followed weeks of negotiations between the Bloc and emissaries of France, whose embassy has been occupied by Bloc militants since May 4, and Venezuela, whose embassy was taken over May 11.

The announcement followed a month of political violence that has cost more than 80 lives here as militant opposition groups struggle against the rightist, militaty-based government.

Although the abandonment of the embassies was scheduled for late this afternoon, it was postponed until Friday morning when a requested Panamanian plan failed to show up here by nighfall. The militants refused to leave in the dark.

This turmoil coincides with the escalation of a long-running civil war in nearby Nicaragua and growing fears that the entire Central American region could be engulfed in civil strife.

Earlier today, San Salvador's downtown cathedral was occupied for the second time this month as six members of another dissent group, the United Front for Popular Action, took over the building and vowed to remain for 72 hours to protest what they said was the recent government killing of several of their members.

The United Front is a peasant-based organization similar to, although smaller them the Revolutionary Bloc, whose militants last week abandoned the cathedral after a three-week occupation.

Meanwhile, foreign diplomats requested a meeting with President Carlos Romero and demanded that Salvadoran authorities provide more protection for them following the murder yesterday of Swiss charge d'affaires Hugo Wey.

Phillipe Couvillier, a member of the French Embassy staff, expressed disappointment this evening that the release of the hostages had been postponed, but said "we have every reason to believe the situation will be resolved tomorrow."

No reason was given by the Revolutionary Bloc or by the foreign negotiators for the failure of the Panamanian plane to appear.

Informed sources speculated that the Bloc's sudden decision to accept a long-standing Panamanian offer for asylum brought on a Panamanian administrative snarl that could not be untangled before nightfall.

Sources said that France and Venezuala had agreed to provide diplomatic protection for the 25 militants until they land in Panama. That might entail some of the negotiators going on the plane.

The sources said that the long-stale-mated negotiations began to move at midday today when Revolutionary Bloc officials visited the French and Venezuelan negotiators and said that they would accept asylum for their comrades occupying the embassies.

Despite widespread support for the immediate goals of the occupations, many here, including San Salvador's liberal archbishop and other opposition groups, had called for them to end as violence increased.

Tension and fear in this troubled Central American republic multiplied Wednesday when Swiss diplomat Wey was murdered by unknown assailants on his way to work.

This country's spasm of violence, now entering its fouth week, began when Bloc militants occupied the French and Costa Rican embassies on May 4.

Both ambassadors and memebers of their staffs were held hostage as the militants demanded that the military-backed government release Bloc leaders who, the organization said, had been arrested. The government denied that they were in custody.

The Costa Rican hostages escaped within a few days, and their captors gave up the embassy and flew to asylum in Costa Rica shortly afterward. Six hostages, including Dondenne, remained inside the French Embassy with 16 militants.

On May 8, 25 civilians were killed by military police during a demonstration on the steps of the cathedral in support of the Bloc. Three days later, nine militants occupied the Venezuelan Embassy, taking eight hostages including Ambassador Santiago Ochoa.

The Venezuelans escaped May 20, and police quickly surrounded the embassy and cut off food and water supplies to the militants inside. On May 22, police opened fire on youths attempting to march through government barricades to bring food to the embassy. Fourteen of the youths were killed.

The next day, leftist guerrillas of the Popular Liberation Forces assassinated Salvadoran Education Minister Carlos Antonio Herrera-Rebollo inretaliation.