Disputes over the location of talks are troubling the recently launched dialogue between the Salvadoran government and the guerrilla movement, according to rebel leaders.

Already the insurgent movement has accused the government publicly of backing out of a meeting that was planned for Sept. 11 after differences arose over the site. Guerrilla representatives traveled to Panama City after the government agreed in principle to meet there, but the government representatives never showed up, a rebel statement said.

In addition, the guerrilla alliance has decided to insist that one of the next two rounds of talks take place in El Salvador, the insurgent sources said in interviews in recent days.

"We will not go to the next meeting if they do not agree to have talks in El Salvador," a rebel leader said.

The rebel sources said the government so far has only proposed sites outside the country, and experienced observers pointed out that right-wing critics of the negotiations would strongly oppose meetings in El Salvador.

The government's chief representative for the talks, Francisco Quinonez, declined to comment about meetings with the guerrillas.

"These are private matters," he said in a telephone interview from San Salvador. When asked about the insurgents' charge that the government had skipped the Panama meeting, he said the accusations were "propagandistic" but did not deny them.

Quinonez and another member of the Salvadoran government's peace commission met guerrilla representatives for the first and only time on Aug. 29 in Bogota, Colombia. The goal was to start a dialogue aimed at a negotiated settlement of the nearly four-year-old Salvadoran civil war.

The problems in setting up another meeting indicate that progress will be difficult in the talks, although it is unclear whether such procedural difficulties could halt the dialogue altogether. One rebel leader said that the Salvadoran government's hands were tied to some extent by right-wing opposition, but he still expressed "moderate optimism" that other political groups in the country favor talks.

The disputes have broken out as the guerrillas intensified their military activities this month in eastern and southeastern El Salvador. A rebel leader said here the guerrillas want to show that they have not been pushed back to isolated enclaves along the northern border with Honduras.

Previously the guerrillas have not commented on their discussions with the government. They changed their minds apparently out of irritation at what they view as foot-dragging by the peace commission.

According to the insurgent sources, the two parties agreed at the Bogota meeting to hold a second session Sept. 11 to choose a site for a higher level meeting later at which substantive negotiations would begin. The date for the higher level meeting was fixed as Sept. 29, according to one top-level official.

In contacts after the Bogota meeting, the guerrillas proposed Mexico as a site; the government suggested Costa Rica. The government apparently rejected Mexico because it is considered friendly to the insurgents, while the rebels said Costa Rica is the site for their meetings with U.S. Central America envoy Richard Stone which they want to keep separate from their talks with the peace commission.

The guerrillas then suggested Panama, and one member of the peace commission reportedly agreed in principle. Guerrilla representatives Oscar Bonilla and Carlos Molina arrived in Panama Sept. 10 and waited until Sept. 14. Then they left, issuing a statement that they still wished "to continue the search for a dialogue."

The rebels proposed in Bogota that a full-scale meeting take place in El Salvador but received no response. Now, they say, the peace commission has suggested Costa Rica, Panama or Bogota. The guerrillas say they would meet in one of those countries providing that the next session be in El Salvador.

"It's okay to meet Stone in another country because he is from the United States, but both sides are Salvadorans in the talks with the government and we should meet in El Salvador," one rebel leader said.