Preliminary election results Monday showed the governing party ahead, but the left made dramatic strides and it was not clear if the rightist administration would retain its congressional majority.

For the first time since the civil war began 11 years ago, a leftist coalition appeared destined to have a strong presence in the 84-member Assembly of Deputies.Sunday's municipal and legislative balloting was the first nationwide election ever sanctioned by leftist rebels, who did little to disrupt the voting and urged supporters to back the leftist Democratic Convergence.

President Alfredo Cristiani's governing Republican Nationalist Alliance, or Arena, said its projections indicated it would have "at least" 43 seats in congress.

But because of the complexity of the formula for apportioning seats, reliable predictions of the composition of the new congress were impossible in the absence of official results.

"Without complete official results, no party can project with certainty the number of seats it will have," said Morgan Bojorquez, statistical analyst for the Channel 12 television station.

The private TV station said early Monday that its projections indicate that Arena received 47.4 percent of the vote; the Christian Democrats, who governed from 1984 through 1989, received 28 percent; and the Democratic Convergence, an alliance of three leftist parties, won 17 percent. The TV station said the rest of the vote was distributed among small parties.

Arena supporters celebrated at party headquarters. To the accompaniment of a mariachi band, they sang their party anthem, which says "El Salvador will be the tomb where the Reds will end up."