El Salvador's new rulers have run into serious internal differences over how to deal with escalating political violence that has presented the 2-week-old government with its first major crisis, sources in that country said yesterday.

The five-man civilian-military junta has made no public appearance or comment since last week. In the meantime, three of its Cabinet ministers remain hostages of armed leftists, a massive political rally erupted into a downtown looting and burning spree and San Salvador's two major newspapers were bombed.

At least 26 demonstrators were shot and killed by security forces Monday and a high-level military official was assassinated, reportedly by leftist guerrillas. On Tuesday, 200 leftists protesting alleged U.S. involvement in the Oct. 15 coup attacked the American Embassy and eventually were repelled by U.S. Marine tear gas.

Yesterday 14 persons were reported killed in three separate clashes around the country.

Sources said in telephone interviews that the left, organized into three major peasant-student-labor coalitions, each with its own guerrilla army, has secceeded so for in preventing the junta from consolidating its control over the Central American country.

Its attacks and demonstrations have come in rapid-fire fashion, and the government has been so busy confronting each day's events that it has had little time to develop promised reform programs it hopes will defuse the political and social unrest that had grown under the deposed rightist, Gen. Carlos Humberto Romero.

At the same time, the sources said, the junta has had trouble developing a unified stand on what to do about these problems and its failure to act forcefully have given the impression that it does not know what to do.

They said members of the junta spent their first week in power closeted in discussions about how to deal with the problem of political prisoners.

In its first announcement following Romero's Oct 15 ouster, the junta decreed the release of nearly 300 political prisoners that human rights organizations had alleged the previous government held in secret jails. After an investigation, however, the junta announced it could find no prisoners, and privately said the missing were presumed dead.

Human rights activists then demanded and investigation and punishment for those responsible for their deaths within El Salvador's security organizations and military. Sources said the junta's three civilian members -- liberal businessmen Mario Andino, Social Democratic politician Manuel Ungo and Catholic academician Roman Mayorga, wanted to appoint an investigatory tribunal, while the two Army officers within the junta balked.

"The military didn't want it," one informed source said, "and some of the garrisons threatened an uprising." With torture and murder of prisoners charged to the military as a whole, the source said, it was believed some of the supposed "progessives" who instituted the coup would have "problems" with such an investigation.

On tuesday, the military, represented within the junta by Col. Jaime Abdul Gutierrez and Col. Adolfo Arnoldo Majano, apparently agreed to the idea and sources said a tribunal is being formed.

Although the coup was launched by so-called "liberal" young Army officers, and at least a dozen high-level officers left the country with Romero, both the left and other more moderate political groups charged that many military rightists associated with past political repression remain in place.

At least two of the junta's civilian members -- Ungo and Mayorga -- had been human rights activists while members of the opposition, and they had denounced the previous government's practice of meeting leftist demonstrators with a hail of bullets that usually left scores of both demonstrators and innocent bystanders dead.

Yet when a similar demonstration occurred Monday, the result was the same. As members of the United Popular Action Front marched through downtown streets, a gunfight erupted that left 26 dead, by government count. While the junta was reportedly furious -- and charged that the Salvadoran National Guard had acted on its own without authorization -- no public statement was made.

The left has taken full advantage of junta indecision and failure to present a forceful program. By the time the new government got around to holding its first Cabinet meeting Tuesday -- in which it reportedly decided to raise salaries and lower prices of basic foods commodities -- three Cabinet members were being held hostage in their own ministries.

The leftist holding them have demanded investigation of political prisoners and punishment of torturers, and called for wage increases and a freeze on food prices.

While the U.S. State Department has indicated it would help the junta find a new and less violent way of dealing with demonstrators, in the form of teargas and other nonlethal weapons sales, any U.S. involvement is likely to add to leftist fervor.

The militant left has charged the United States with orchestrating the coup to get rid of Romero and ease repression while heading off a leftist revolution. While the United States had admitted knowing about the coup in advanced, it has denied involvement.

All those participating in the new government have been branched "U.S. puppets" by the left and on Tuesday, violence shifted to the U.S. Embassy.

Such an attack has long been expected. The embassy in San Salvador is probably the best protected in Latin America, and Ambassador Frank Devine is the most heavily guarded U.S. diplomat in the hemisphere.

In addition to a 12-man Marine guard contingent, Devine is assigned a State Department security contingent that accompanies his bullet-proof limousine in cars in front of and behind him whenever he ventures out of the building.

Devine was not inside the embassy when the protesters, the Popular League-28, reached the building Tuesday afternoon. Instead, the leftists were met by armed Marines on the roof, and guards standing behind the foot-thick concrete slabs that last year were constructed in front of each entrance.

By the time combat-equipped National Guard troops arrived at the scene, the Marines reportedly had dispersed the crowd with tear gas. Two Marines incurred minor wounds in the process.