SAN SALVADOR, NOV. 8 -- Two more victims of death squad-style killings were discovered today, raising tensions over the imminent release of political prisoners under an amnesty law and the planned return of exiled left-wing rebel leaders.

Two unidentified men were found beaten to death along a highway about seven miles south of the capital in a manner reminiscent of the right-wing death squads that have been blamed for some 40,000 murders since El Salvador's civil war began in 1979.

The bodies of the two men, who appeared to be workers or peasants in their 20s, had the initials "FDR" written on their chests in red ink. The apparent reference to the leftist Democratic Revolutionary Front, known by its initials in Spanish as the FDR, was seen here as a warning to its leaders not to go through with plans to return to El Salvador from exile.

The FDR, headed by leftist politicians opposed to the centrist government of President Jose Napoleon Duarte, is allied with the Farabundo Marti National Liberation Front, a Marxist-led coalition of five armed guerrilla groups.

In an earlier killing widely blamed on a renewal of death-squad activity, the president of a nongovernmental human rights commission, Herbert Anaya, was shot to death Oct. 26.