Gunshots rang out in clashes between foes and supporters of President Hugo Chavez today, leaving at least five people wounded as the opposition stepped up street protests in its drive to force the Venezuelan leader to resign.

Demonstrators and police ran for cover after gunfire was heard near the center of the capital, breaking an uneasy holiday calm that had settled over the streets during a 33-day-old opposition strike against Chavez. Four people were hit by the gunfire and another person was injured by police shotgun pellets, fire chief Rodolfo Briceno said.

It was unclear who had opened fire. At least 12 people were hit by stones or bottles.

National Guard troops fired tear gas and shotgun pellets to stop a few hundred Chavez supporters from attacking thousands of opposition marchers. Confused running battles broke out with troops as both sides threw bottles and rocks.

Columns of smoke wafted high above apartment buildings in the southwest part of Caracas as pro-Chavez demonstrators set up burning barricades near Fuerte Tiuna military base to block opposition marchers who were demanding that the government free Gen. Carlos Alfonso Martinez, a dissident officer detained this week.

The opposition strike, which started Dec. 2, has choked oil shipments and stoked fears of violence in the world's fifth-largest petroleum exporter. Global oil prices have hit two-year highs because of the strike and the fear of a U.S. war with Iraq.

Opposition leaders are locked in a stalemate with the government, and vowed to continue the strike until Chavez quits and accepts early elections. They have held daily marches and urged supporters not to pay taxes. But the populist president has refused to quit.

Opponents and supporters of the president have been caught up in a bitter political conflict for more than a year, and rival rallies and marches have often ended in violence. Foes of Chavez said he has failed in his electoral promise to tackle poverty and corruption. Instead, they said, his self-styled revolution has driven Venezuela toward economic ruin with left-wing reforms and mismanagement.

Since his 1998 election, Chavez has portrayed himself as a champion of the poor in a nation where slums sit uneasily alongside rich neighborhoods. Despite Venezuela's vast oil wealth, most of its people live in poverty.