Updated

Venezuela's army chief on Monday condemned an opposition strike he said had sabotaged the nation's key oil industry and overstepped the boundaries of democracy.

In a blow to leaders of the 15-day-old general strike against President Hugo Chavez, Gen. Julio Garcia Montoya called on citizens to distrust opposition leaders mounting "an irrational and brutal action against the country."

Garcia Montoya criticized protests that blocked Caracas highways and roads Monday. He said in a televised speech that "society is strengthened through its reconciliations and not through its conflicts."

It was the clearest position the armed forces has taken yet on the general strike, which has crippled oil exports in the world's fifth-largest oil producing nation. Oil prices soared Monday.

Also Monday, police fired rubber bullets into several apartment buildings after protesters demanding Chavez resign blocked highways and roads and threw stones at police in several Caracas neighborhoods.

Enraged Chavez backers tried to break an opposition push to paralyze Caracas as the metropolitan area of 7 million people became increasingly lawless.

Soldiers with assault rifles lined up outside a police station occupied by the army as opposition marchers demanded the troops leave. As the crowd grew, the soldiers retreated and police in riot gear fanned out to keep hundreds of opposition and Chavez supporters apart. Chavez ordered the army takeover of the city's police precincts in November.

The White House again urged Chavez to call early elections, but seemed to modify its stance by stressing -- as Chavez has insisted -- that those elections be held under rules spelled out in Venezuela's constitution.

Chavez has rejected demands for his resignation and early elections, saying the constitution doesn't allow them until August, the midway point of his current six-year term.

He has ignored courts that ordered him to give back seized gasoline trucks and return control of the police department to Caracas' opposition mayor. Chavez told military commanders Sunday that he -- not the courts -- gives their orders.

Using the slogan "Block your block," the frustrated opposition launched its "takeover of Caracas" after the economically devastating strike seemed only to strengthen Chavez's resolve.

Skirmishes between Chavez supporters and opponents erupted in several parts of Caracas and other cities as outnumbered police officers and national guard troops desperately tried to keep them apart.

"You can't throw rocks at police!" one officer pleaded with residents of a central neighborhood.

Above him, opposition supporters leaned out of windows banging pots and pans. Officers fired rubber bullets at the buildings, breaking windows and sending residents scurrying for cover. The sting of tear gas filled the air.

On the Prados del Este highway, opposition and government supporters, separated only by the highway median, skirmished with rocks and bottles.

"We're not leaving," said Ana Reina, a 58-year-old retired teacher, one of about 1,000 opposition supporters on the highway. "The police never come when there's a mugging or a robbery -- just when they want to coerce us. But we're not afraid."

Across the median, Gisela Perez, a 42-year-old street vendor, said she wasn't leaving either. She and about 200 others were defending Chavez, whose 1998 election ended 40 years of alternation between two U.S.-aligned -- and corrupt -- political parties.

"If we waited 40 years, they can wait until August 2003 for a referendum," she said. "If they try to get rid of our president like this, we're going to kill one another."

The opposition marches sought to expand a protest that drew more than 1 million people into the streets Saturday.

"The only thing we ask of you is to call elections now," opposition leader Carlos Ortega said in comments directed at Chavez.

The opposition resents Chavez's alliances with countries such as Cuba, Iraq and Libya, his discourse of class conflict and his mishandling of the economy.

A similar opposition campaign in April ended in violence that killed 19 people and sparked a military coup that ousted Chavez for two days. His supporters rallied when a new government dissolved the constitution and he was restored to power.

Chavez has tried to break the strike by seizing fleets of striking gasoline tanker trucks and sending new crews onto ships anchored in protest.

On Sunday, heavily armed troops helped a foreign crew board the Pilin Leon, a tanker anchored in western Lake Maracaibo that has become a symbol of the strike. But the ship remained motionless Monday, and state officials said they were awaiting the arrival of another captain.