Salvadoran revolutionaries assissinated the minister of education and his driver today in apparent relaliation for the killing by police of 14 youthful protesters last night.

It was the latest turn in cylces of violence that have made El Salvador, along with nearby Nicaragua, a threat to the stability of all Central America a region long troubled by the disparity between the rich who rule and poor masses now in rebellion.

The latest killings here brought to 70 the number of deaths in escalating confrontations between the military-dominated government and student-peasant rebel groups since May 4. On that date, the main non-guerrilla group of protesters in this crowded nation occupied the first of several embassies and churches.

Police said Education Minister Carlos Herrera Rebollo, a Christian Democrat, and his wife were assaulted by gunmen in a passing car as he was driven to work this morning. Mrs. Herrera was slightly wounded.

Several hours later, the guerrilla Popular Liberation Front announced in phone calls to the media that it had killed the minister in retaliation for what it described as the "massacre" last night outside the Venezuelan Embassy.

According to witnesses, about 100 youths had marched on the embassy carrying food to nine militants of the student-peasant Popular Revolutionary Bloc who have occupied the building since May 11.

Since the escape Sunday of the occupiers' chief hostage, the Venezuelan ambassador, the police have attempted to cut off food and water to those remaining inside.

Venezuela, in response to the latest violence, sent in three military aircraft and flew home 50 Venezuelans living in El Salvador, the Associated Press quoted a diplomatic source as saying.

Witnesses to last night's killings said the firing began when the marchers, who had separated into two groups to approach the embassy from opposite ends of the street, meet with military roadblocks.

Just as during in May 8 downtown demonstration in which 25 civilians were fatally wounded, it was unclear who fired the first shot. After several minutes of automatic weapons fire from police, 14 youths lay dead. Twenty youths were wounded and no police casualties were reported.

Police pointed out several small-caliber pistols lying beside some of the bodies. But some witnesses said that neither the positions where the guns lay nor their clean condition corresponded to the bloody hands of the dead.

To the military, those pistols-and the 125 military and police officials killed by guerrillas over the past 10 years, including 12 this month-are justification for orders to shoot with all available firepower first and ask questions later.

Retaliation for the murder of the education minister is now awaited.

Tonight, President Carlos H. Romero imposed a state of siege, suspending for 30 days such constitutional guarantees as protection against arrest without charge. A spokesman said the measure resulted from the "wave of violence culminating with the minister's death." The legislature approved imposition of the emergency rule.

[In Washington, a State Department spokesman said, "We condemn the tragic assassination of the minster of education and his driver. Such violence is no answer to any of the problems facing that county . . . the violence must be brought to end." The United States has singled out El Salvador in the past for aid cuts because of human rights violations.]

According to the government, the guerrilla group claiming responsibility for the minister's death is the armed branch of the Popular Revolutionary Bloc, a coalition of student and peasant groups that organized in the early 1970s and now claims 30,000 members.

This Bloc advocates socialism, which is anathema to the military, but awows nonviolent aims such as salary increases for peasants.

The Bloc, as well as two other groups that also deny guerrilla ties, protests social and economic conditions here. So does the government. There is little disagreement that El Salvador, smaller than Maryland but with 4 million people, has a near feudal system in which most land is held by a small wealthy elite and farmed by underpaid peasants.

In recent years, peasant activits have been joined by poorly paid blue-collar workers in the coutry's growing industrial sector. Both sectors are eminently open to militant organization.

Most of the industry also is owned by the small wealthy class, which traditionally has support military rule. Following the kidnappings and murders by guerrillas, many in the elite now worry that perhaps the hard line is failing to maintain order.

The elite now wants to talk - with cowed opposition political groups and with the dominant Roman Catholic Church - about trying to imporve conditions for the masses and allowing a political opening.

But for many in the military, the time for talk is only after elimination of what it perceives as an international communist conspiracy to overthrow it.

"The left doesn't permit us to resolve the problems here," said one high-level military officer. "We don't have time to make good government."

San Salvador Archbishop Oscar Romero is outspoken on the subject of human rights and this year has been nominated for the Nobel Peace Prize by British and U.S. lawmakers.

But the local church leadership is divided for and against the archbishop as the most prominent opposition voice here. An unknown number of liberal priests are believed to have some direct knowledge of the guerrillas, but the vas majority are pacifists who counsel their parishoners to unify and persevere peacefully in trying to better their lives.

The government, however, persists in persecuting local priests. This, too, has turned people against the government.

Last month, for instance, a popular small-town parish priest was arrested after guerrillas shot and killed the town mayor. The priests, who was seeking permission for a fundraising bar-becue, was talking to the mayor in the town square when the shooting occurred.

The priest's thumbs were tied together with nylon fishing line, a common substitute for handcuffs that cuts off circulation and causes painful swelling, and he was beaten, suspected of having set up the mayor for the assault.

Hundreds of wailing townspeople surrounded the local jail throughout the day he was held until he finally was released the next afternoon.

The priest went into temporary seclusion and when the returned to celebrate Mass last Sunday, residents ran to pack the church, singing and applauding. Women embraced him and called him "little father" and sundried old men stood crying with their hats in their hands.

"The man is an agitator," answered a military official when asked about the arrest and beating. "He has clan-destine contacts. Don't make a martyr out of him. What's worse - that somebody got killed, or that the priest got locked up?"