At least 7,000 demonstrators defied a government-imposed state of siege today in a burial procession for seven of the 14 youths killed by military police Tuesday. Later, in the same cemetery, the government buried Education Ministry Carlos Antonio Herrera-Rebollo, assassinated by leftist guerriallas Wednesday.

While Herrera-Rebollo's funeral, attended by at least 3,000, including President Carlos Romero and most of his Cabinet, was taking place, members of the Popular Revolutionary Bloc announced the end of their three week occupation of San Salvador's main cathedral and other local churches.

A spokeman for the bloc, whose militants still occupy the French and Venezuelan embassies here, said the militant peasant-student organzation had achieved its cathedral goals of "denoucing and bringing international attention evidence of repression and increasing solidarity."

Spokeman Julio Flores said, however, that the militants would remain in the embassies until the government of EL Salvador guarantees them amnesty.

The government has offered the militants a choice of jail or safe conduct to asylum in another country, both of which they have refused. The Bloc seems satisfied that at least the French government has complied as much as possible with a Bloc members allegedly arrested in April.

The government has denied ever having the three in custody. Eight hostages held in the Venezuelan Embassy escapaed Sunday, and miliants occupying the building - still considered foreign territory - are surrounded by police and cut off from food and water.

Flores also indicated that the Bloc realized that approximately 75 persons inside the cathedral could no longer depend on even minimal legal guarantees under the state of siege.

The state of siege was declared yesterday after guerrillas of the Popular Liberation Front killed Herrera-Robollo and his chauffer. It prohibits all public gatherings and allow arrest without charge and searches without warrants.

Although Romero said early in the day that it would be "strictly enforced," the Bloc funeral march was allowed without incident. A government official pointed out that there were two funerals scheduled for the day, and that one could hardly be repressed when high government officials would be in the streets for the second.

Meanwhile, a national forum called for by President Romero last week for all "legal" political and social groups to discuss growing violence here began today with the noticeable absence of the country's main opposition parties and unions.

Spokemen for the leading opposition Christian Democratic Movement, the National Democratic Movement and many of EL Salvador's largest union federations said they were boycotting the talks because the government had given them no proof of its interest in democracy.

Citing the killing of 14 youths, the state of siege and the fact that San Salvador's archbishop, an influential government critic, peasant unions and others, were not invited to the talks, the politicians said that "repression and demorcracy cannot coexist."

The opposition leaders called instead for a "popular forum" with participation of all factions, including leftist groups and the Bloc, to address longstanding social, enconomic and political problems and to bring an end to the past four weeks of bloodshed.

The 14 youths were killed as they marched to the Venezuelan Embassy to bring food to the militants inside. Military police at roadblocks ordered them to stop and opened fire after a gunshot of undetermined origin was heard.

Tuesday's killings came exactly two weeks after 25 civilians were killed or fatally wounded when military police shot at a group in front of the cathedral demonstrating in support of the Bloc occupations.

In constrast in recent weeks that have been composed mainly of youths, young militants in today's two-mile march from the cathedral to the cemetery were joined by large numbers of well-dressed middle-aged people, poor peasants from the countryside and families. The marchers kept in close ranks, their eyes constantly darting from buildings to the street ahead looking for military police.

"we know we are all in danger," said one man who carried a young child in his arms. "We are all fighting here and we've got keep together." The man said he was an automobile mechanic and not a member of the Bloc.

I support what they stand for," he said. "We all live in the same economic situation. We are poorly clothed., poorly housed and poorly fed."