General strike leader Carlos Fernandez was seized at a restaurant by gunmen who identified themselves as secret police agents, Venezuela's largest business chamber said.

Fernandez, president of the Fedecamaras business chamber, was the co-leader of a two-month strike that sought President Hugo Chavez's ouster. The strike ended earlier this month in all but Venezuela's oil sector.

Fernandez was detained about midnight Wednesday, said Fedecamaras vice president Albis Munoz. His whereabouts weren't known and there was no immediate comment from the government, she told a news conference.

"We know absolutely nothing about his whereabouts," Munoz said, adding that Fernandez was arrested without any court order. "We demand that the government guarantee his safety."

Foreign Minister Roy Chaderton, attending a summit of non-aligned nations in Malaysia, told The Associated Press he had no information on Fernandez.

Fernandez had been under government investigation for his role in the strike, which crippled Venezuela's economy. Chavez has repeatedly accused strike leaders of trying to topple his government and threatened they would be prosecuted.

Strike co-leader Carlos Ortega of the Venezuelan Workers Confederation condemned the arrest as "a terrorist act" that presaged a wave of repression against Venezuela's opposition.

The arrest followed the slayings and possible torture of three dissident Venezuelan soldiers and an opposition activist this week.

Human rights groups warned a continuing impasse between Chavez and opponents demanding early elections could lead to more violence.

All four bodies were found in the suburbs of Caracas with their hands tied and their faces wrapped with tape.

Darwin Arguello, Angel Salas and Felix Pinto and opposition activist Zaida Peraza, 25, had multiple bullet wounds and showed signs of torture, Raul Yepez, the deputy director of Venezuela's forensics police, said at a press conference on Wednesday.

According to the New York-based Human Rights Watch, a witness to the abductions saw the victims being forced into two vehicles by men wearing ski masks, not far from the plaza that has become the central rallying point of the opposition. Yepez said the abduction took place on Saturday night.

"I don't think anybody should expect the violence to decrease," said Michael Shifter, an analyst at the Inter-American Dialogue think tank in Washington. "As long as there is an impasse on both sides, if anything, the violence will increase."

Dissident soldiers supported a nationwide strike called Dec. 2 to demand Chavez's resignation or early elections. The strike was lifted Feb. 4 in all areas except the oil industry to protect businesses from bankruptcy.

Chavez's opponents, including other dissident military officers, said government sympathizers could have been responsible for the killings. But Yepez said police had "practically ruled out" political motives.

No arrests have been made in connection with the killings.

Chavez was elected in 1998 and re-elected in 2000. He promised to wipe out the corruption of previous governments and redistribute the country's vast oil wealth to the poor majority.

His critics charge he has mismanaged the economy, tried to grab authoritarian powers and split the country along class lines.

Opponents of Chavez said Wednesday that more than 4.4 million Venezuelans had petitioned for a constitutional amendment to cut Chavez's term in power from six to four years.

Organizers said they had counted and verified 3.7 million signatures collected in a nationwide petition drive on Feb. 2. These were added to another 719,000 signatures supporting the initiative already gathered.

Under the constitution, organizers need signatures from 15 percent, or about 1.8 million, of the country's 12 million registered voters, to force a referendum on the amendment. This would then clear the way for general elections later this year.