By JUAN FORERO
 
CARACAS, Venezuela, March 3 — The Organization of American States met Wednesday with electoral officials and opposition leaders in a last-ditch effort to find a peaceful solution to Venezuela's political turmoil, while opponents of President Hugo Chávez called for a major protest march on Thursday.

The situation here has remained tense since the National Electoral Council announced on Tuesday the disqualification of hundreds of thousands of signatures needed to allow a recall referendum on Mr. Chávez.

The president's foes charged that the leftist government pressured electoral authorities to disqualify the signatures in order to derail a referendum, since a successful recall would end Mr. Chávez's tumultuous five-year rule. The opposition leaders contended they had collected more than enough signatures to permit a recall on Mr. Chávez, whom they have fought to oust over the last two years through legal maneuvers, a failed coup, strikes and protests.

But though Western diplomats monitoring the recall effort agreed that the opposition had the required valid signatures, the Electoral Council ruled Tuesday that the effort had fallen 600,000 short of the 2.4 million needed.

Electoral officials have proposed a two-day "repair period" in which about 1.1 million voters could confirm the validity of signatures sidelined by the council. The opposition argues that the two-day time limit is intended expressly to sink the referendum.

"Under these fraudulent conditions, it is impossible to go to the repair period," Timothy Zambrano, an opposition leader, said in an interview.

The Electoral Council announced Tuesday that 876,017 signatures displayed signs of similar handwriting, and that an additional 233,000 were disqualified for other reasons. Independent observers said that, in many cases, volunteer workers had filled out petition forms but that citizens had signed them.

The Organization of American States and the Atlanta-based Carter Center, observers at the December signature gathering, called the signature collection fair and urged that "excessive technicalities" not get in the way of the will of the people.

Still, diplomats monitoring the work of electoral authorities said that unless the opposition went along with the repair period, Venezuela could be plunged into a period of violence. "There is still a path leading to a recall," one diplomat said.

American officials, despite voicing "real concerns" about the Electoral Council's decision, have recommended that the opposition negotiate a workable, logistically sound agreement that will permit signatures to be quickly confirmed.

Fernando Jaramillo, chief of mission for the O.A.S., said his organization was not pressing the opposition to accept the council's conditions. But he said that if the verification of signatures takes place, the organization will try to ensure that 100 international observers are in place.

The opposition has proposed that the Electoral Council simply publish the names of all signers and allow those whose names may have been falsely included to scratch themselves from the list. The council, though, is unlikely to go along.

The opposition has threatened to pick up the pace of protests, but faces a formidable opponent in a president who has consolidated his power. Polls show that more than 40 percent of Venezuelans support Mr. Chávez, and his government is enjoying an economic rebound after two disastrous years.