President Alfredo Cristiani says a spate of new rebel attacks could derail peace talks, but the rebels say the attacks intend to pressure Cristiani into returning to the negotiating table.

Fighting broke out in half of El Salvador's 14 provinces on Tuesday, with a series of rebel strikes that began early in the day leaving at least 27 people dead and 141 wounded, officials at the scene said.Sporadic shooting could be heard during the night on the outskirts of San Salvador.

The Farabundo Marti National Liberation Front, the rebel organization also known as FMLN, denied it had launched an offensive. It said the attacks aimed to prod Cristiani's government back to the negotiating table.

Government and rebel representatives have held five rounds of talks since May. Negotiations were to resume Nov. 4 in Mexico but bogged down over bitterly differing positions on the future role of the armed forces.