Labor union leader Carlos Ortega, who faces treason charges, entered the embassy earlier Friday, Costa Rican Ambassador Ricardo Lisano said.

"For humanitarian reasons ... (Costa Rica) decided to grant asylum and it has communicated as much to the Venezuelan government," the Costa Rican foreign ministry said in a statement.

The statement said Ortega cited fear for his personal security when he requested asylum. He had been in hiding since Feb. 20, after a judge issued a warrant for his arrest for treason, rebellion and incitement.

Hundreds of flag-waving supporters gathered around the Costa Rican embassy in eastern Caracas chanting, "Ortega, friend, the people are with you!"

Ortega, head of the country's largest labor union, helped orchestrate a general strike to demand early elections or Chavez's resignation. The strike, which petered out last month, paralyzed Venezuela's lifeblood oil industry and cost the country $6 billion, according to government estimates.

Last month, authorities arrested strike leader Carlos Fernandez, president of Venezuela's largest business association. He is under house arrest pending trial on charges of rebellion and instigation. A judge struck down a treason charge.

Arrests warrants also are out for seven executives of the state-oil monopoly, Petroleos de Venezuela S.A. The seven are in hiding.

Secret police stormed an opposition march Saturday in an attempt to arrest oil executive Juan Fernandez, who made a surprise brief appearance. The police clashed with protesters, and Fernandez escaped.

Opposition leaders have denounced the arrest warrants as political persecution. Chavez says strike leaders must be imprisoned for at least 20 years for inflicting suffering on the population.

Ortega is third Chavez opponent to seek asylum abroad.

Last year, Colombia granted asylum to business leader Pedro Carmona, the figurehead in an April coup that ousted Chavez for two days. El Salvador granted asylum to another alleged coup leader, Vice Admiral Carlos Molina Tamayo.

Chavez opponents accuse him of steering Venezuela's economy into recession with leftist policies. They also say he has accumulated too much power under the guise of a "social revolution" to help the poor.

Chavez says his foes resent his efforts to end social inequality and his success in wresting power from two corrupt traditional parties that ruled Venezuela for 40 years until his 1998 election.

Chavez fired 15,000 workers from the oil monopoly — almost half the work force — for participating in the stoppage. He has threatened to close down four private television stations that gave supportive coverage to the strike.

Venezuela's oil industry — the source of half of government income and 80 percent of export revenue — is recovering from the strike. Oil production has reached 2.9 million barrels a day, according to the government. Fired PDVSA executives say it's only 2.1 million barrels a day, about two-thirds of what it was before the strike.