Caracas, Venezuela ? The government detained the striking crew of a tanker and moved the gasoline-laden vessel toward port Saturday as the nationwide work-stoppage against President Hugo Chavez dried up Venezuela’s gas supplies.

Leaders of the 20-day-old general strike accused Chavez of using a Cuban crew to pilot the Pilin Leon, which had been moored offshore after the crew joined the strike. Carlos Fernandez, a strike organizer and president of the Fedecamaras business chamber, said the use of Cubans “violates national sovereignty.”

A source at the Cuban Embassy in Caracas, speaking on condition of anonymity, denied the claim, calling it a “lie.” State TV said Venezuelans were piloting the ship. Chavez’s rivals often accuse the president of being too close to communist Cuba.

Government security forces detained the Pilin Leon’s captain and crew Friday night, Cuiro Izarra, international commercial manager of the state oil company, told told Globovision TV. On Saturday, the vessel was heading toward a port in Maracaibo Lake.

The takover of the vessel came as gasoline supplies in Venezuela began drying up Saturday, creating a specter of food shortage. Britain joined the United States and other nations in urging its citizens to leave Venezuela, fearing shortages will spark violence.

The strike, launched Dec. 2 to force Chavez from office, has crippled oil production in the world’s fifth-largest exporter of crude and sent global oil prices climbing.

Defense Minister Jose Luis Prieto went on television to urge all striking oil workers to obey a Supreme Court ruling ordering on them to immediately return to work. Otherwise, he said, they “will be subject to sanctions.”

Most gasoline stations were shut and the National Guard stationed at the few that were open tried to keep impatient motorists in lines that were blocks long.

Leaders of the strike vowed to maintain the stoppage until Chavez resigns or calls early elections.

The president’s opponents say he has mismanaged the economy, widened class divisions and intends to impose a Cuban-style leftist state in this South American country of 24 million.

The government is insisting that Chavez will not bend.