By CHRISTOPHER MARQUIS
 
WASHINGTON, May 14 - Political turmoil in Venezuela is rising just two weeks before signers of a petition to recall President Hugo Chávez are required to stand by their signatures.

The latest dispute pits Venezuelan electoral authorities against the Organization of American States and the Carter Center, which were invited to oversee and validate the recall process.

A nasty fight erupted over a technical point this week, prompting the president of the National Electoral Council to threaten to expel the foreign monitors for supposedly being partial to the opposition groups seeking Mr. Chávez's ouster.

Francisco Carrasquero, the president of the council, which is dominated by supporters of Mr. Chávez, demanded an apology from the observer groups for actions that Mr. Carrasquero said jeopardized their neutrality.

But the O.A.S., a 34-nation hemispheric group, and the Atlanta-based Carter Center refused. Instead, they issued what they called a clarification of their position.

A Venezuelan official said Friday evening that both sides were trying to cool down the dispute, but two representatives of the monitors said they could still be expelled.

The dispute centers on whether Venezuelan petitioners will be allowed to withdraw their names - as the council insists - during the correction period.

The standoff is one of several developments this week that grabbed headlines and left many Venezuelans and foreign officials scratching their heads. In addition to the dispute with the election monitors, Mr. Chávez and his loyalists recently asserted that they had thwarted a foreign-backed coup, and his government ordered American military officials to leave Venezuelan bases.

Early in the week, the police raided a ranch outside Caracas, the capital, and arrested scores of Colombians dressed in Venezuelan military fatigues. The Colombians, who were not armed, appeared to be under the direction of Venezuelan officers involved in a plot to oust or kill Mr. Chávez, Venezuelan officials said.

Some of the captured Colombians said they had been lured to Venezuela with promises of jobs and residency, The Associated Press said. Colombian and Bush administration officials say they do not know who these supposed mercenaries are, but an investigation is under way and Colombia's foreign minister visited Caracas on Friday and pledged to find out. Venezuelan officials said the owner of the ranch was a Cuban exile who opposed Mr. Chávez.

As that drama unfolded, Mr. Chavez , who has long alleged an American conspiracy against him, demanded that the Bush administration withdraw its officers from Venezuelan bases where they serve as military liaisons.

There is profound animus between Mr. Chávez and Bush officials for what he says was their early embrace of a coup attempt against him in 2002.

The Bush administration agreed to withdraw the personnel - about 20 workers from four sites - and relocate them to the American Embassy, a State Department official said.

The department voiced support for the international observers in their clash with Mr. Carrasquero and the electoral council.

Mr. Chávez, himself a onetime coup plotter who was elected president in 1998, has sought to beat back a determined drive by opposition groups to stage a referendum to recall him from office.

Venezuelan opposition leaders delivered 3.4 million signatures in December to demand a recall vote. The electoral council determined that only 1.8 million signatures were valid, leaving the petitioners about 600,000 signatures short of the required number.

Both sides have since agreed to a plan to determine the legitimacy of signatures that were filled out by people other than the signer; on May 28 and 29, about 876,000 Venezuelans will have the opportunity to verify their signatures. If they do not come forward to certify their signatures, their names will be declared invalid on the recall petition.

Mr. Chávez has resisted this approach, and he most recently asserted that Venezuelans should have the option not just to verify signatures but to remove them altogether.

Venezuela's ambassador to Washington, Bernardo Álvarez Herrera, said the government merely wanted to comply with the rules as laid out by the electoral council.

"We want the prepared process to go ahead," Mr. Álvarez said. "What is important is to have an impartial and fair observation process."

Mr. Chávez's critics say the latest issue is part of a strategy to intimidate signers into retracting their names. Bernard Aronson, a former assistant secretary of state for Latin America, said Mr. Chávez and his sympathizers had sought to thwart the recall effort at every turn.

"Chávez has been playing rope-a-dope with the recall ever since it began," said Mr. Aronson, who is now managing partner of Acon Investments. "He wants to delay and complicate the process. So far, he has succeeded."