The State Department denounced political leaders of the leftist guerrillas in El Salvador yesterday for failing to repudiate the shooting deaths of four U.S. Marines in a cafe ambush two weeks ago, saying they are trying to avoid "the condemnation which that crime deserves."

In a strongly worded statement, spokesman Edward Djerejian said recent remarks by guerrilla official Ruben Zamora make him "an apologist for terrorism" and "represent a twisted use of logic to justify an unjustifiable act."

Guerrillas killed 13 persons, including four U.S. Marines and two U.S. businessmen, at an outdoor cafe June 19.

The FDR/FMLN -- the joint command of the Farabundo Marti National Liberation Front and the Democratic Revolutionary Front -- later claimed responsibility for killing the Marines, saying: "As long as there is more Yankee intervention, more U.S. Marines will die."

Zamora noted in an interview with The New York Times last week that his party, the Popular Social Christian Movement, part of the FDR, condemned the "terrorist killings."

But he added that U.S. military personnel are "targets just like Salvadoran soldiers . . . part of the war and subject to the laws of war." He also said Salvadoran President Jose Napoleon Duarte "is head of the armed forces, and as such he is a target as a military leader."

Djerejian said Zamora "by inference is advocating the murder of a democratically elected president."

He quoted Guillermo Ungo, another political leader and former Salvadoran vice-presidential candidate, as saying his FDR faction, the National Revolutionary Movement, "does not share in or approve of all the actions that some of our allies may carry out."

Ungo's statement was "equivocal" and "an effort by colleagues of the murderers to distance themselves from this barbaric act," Djerejian said.

He called upon "all those linked to the Salvadoran insurgency" to condemn the murders and join talks proposed by Duarte on "humanization of the conflict."