Leaders of a strike aimed at forcing Hugo Chavez from office said they were not intimidated by the president's threats to fire striking managers of the state oil monopoly and vowed the protest would continue through Christmas if necessary.

"Cost what it may, we will continue with this strike," Carlos Ortega, the president of Venezuela's largest trade union confederation, said Sunday. "The authoritarianism and violence of the Chavez regime will not force us to retreat."

Ortega insisted citizens were "resolved to spend Christmas in the streets" protesting Chavez's rule.

Chavez, who has already sacked four executives at state oil company Petroleos de Venezuela SA, vowed more dismissals and said strikers would be prosecuted. The stoppage, which entered its 22nd day Monday, has paralyzed an industry that provides more than 70 percent of the country's export revenue and is the fifth largest supplier to the world.

"We have begun to recover PDVSA and we will start a cleansing in PDVSA," Chavez said during his weekly television and radio show Sunday. "Those who didn't show up for work ... well, they will be fired."

Chavez seized a gasoline-laden ship whose crew joined the strike by dropping anchor in western Venezuela's Lake Maracaibo. Soldiers then moved the tanker Pilin Leon to shore after Friday's seizure.

A judge freed the crew from jail Sunday but prohibited them from leaving the country.

Twelve other tankers remained idle in various ports, though the crews of two of the vessels have also been forced off and arrested, according to lawyer Gonzalo Himiob.

Chavez announced that the government has exported more than 2 million barrels of oil to the United States, the largest customer for Venezuela, in the last nine days. Another tanker carrying 500,000 barrels will leave port in the next hours, he said.

However, oil exports have been cut by about 90 percent since the strike began Dec. 2, helping drive up world prices.

Chavez said in an interview Sunday that the government has activated emergency measures to import gasoline from Brazil and Colombia. He also told Brazil's O Estado de S.Paulo newspaper that Russia offered to send oil tankers.

Business, labor and opposition political parties called a general strike Dec. 2 to demand Chavez step down or submit to early elections, accusing him of failing to revive the economy, widening class divisions and ruling autocratically. Under Chavez, Venezuela's economy shrank 6 percent in the first nine months of this year, unemployment has climbed to 17 percent and inflation to 30 percent.

His popularity has slipped to about 30 percent, though it remains as high as 45 percent in the slums that ring Caracas.

Chavez, a former army paratrooper commander who led an unsuccessful coup in 1992, was elected in 1998 and re-elected in 2000, on promises to help the poor. The president is not constitutionally obligated to submit to a recall referendum until halfway into his six-year term, or August.

The National Elections Council, however, has accepted a petition signed by more than 2 million people calling for a nonbinding vote Feb. 2. Voters swarmed to registration centers across the country even though Chavez vowed to ignore the referendum's outcome.

The oil strike has been a crucial force behind the Venezuela protest, which also has closed down sea ports, many schools and shopping centers. Hundreds of thousands of Chavez opponents have marched in Caracas.

But more and more small businesses opened in downtown Caracas, which has bustled with street vendors and traffic throughout the strike.