Nationalist lawmakers on Wednesday slammed Indonesia's moves to make peace with rebels in Aceh province, saying they don't believe the guerrillas intend to drop their separatist goals despite their latest talks with the government.

Lawmaker Djoko Susilo said he was "pessimistic" that there would be any positive results from the government's fourth round of talks with the Free Aceh Movement, which concluded on Tuesday in Finland.

"So far, the talks have only benefited the rebels, not us," said Susilo, a member of the commission on defense and foreign affairs. "We have to be careful with their hidden agenda in which they want a separation from us."

Rebels in Aceh have been fighting for independence since 1976 in a conflict that has killed at least 15,000 people since 1990. Efforts to end the fighting collapsed in 2003, but the peace process was revived after the Dec. 26 tsunami that devastated the oil- and gas-rich province.

Jakarta has said it will not allow the region to separate from the rest of the country, but would give it a greater say in running its affairs.

The rebels have publicly dropped their independence demand and agreed to a form of self-government within Indonesia.

Some lawmakers reacted positively to reports of progress in the peace process, saying that a lasting peace in the oil and gas-rich province was now in sight.

Envoys from both sides said the latest round of negotiations went well, and negotiators were planning to meet again in Helsinki in July.

"The possibility is now there," analyst Agus Wijoyo said. "There are windows of opportunities that could facilitate the meeting of an agreement between both sides," said Wijoyo, a retired three-star general.

But nationalists in the Indonesian government and the parliament are suspicious of the process, which they say is "internationalizing" a domestic issue.

Another lawmaker, Ribka Proletariyati, said that the government should be "careful" as the talks progress. "We know that (Free Aceh Movement) really wants to separate from us," he said.

Some analysts have warned that the military, which has extensive business interests in Aceh, could scupper any deal.