President Hugo Chavez, whose ties to Cuba and Iraq irked the United States, stepped down Friday after a massive opposition demonstration ended in the deaths of at least 13 people.

The former army paratrooper, 47, presented his resignation to top military commanders when they confronted him in his presidential palace. Dressed in the same outfit he wore when he led a failed 1992 coup – military fatigues and a green beret – Chavez left the palace before dawn and was detained in Caracas' Fort Tiuna army base.

Thursday's protest, 150,000-strong, became bloody when Chavez ordered National Guard troops and civilian gunmen, including rooftop snipers, to stop the marchers from reaching the palace, military officers said. At least 110 people were wounded in downtown Caracas.

Opposition to Chavez's three-year presidency had been mounting for some time. His popularity ratings, at one point soaring to 80 percent, plummeted to below 30 percent this year after he repeatedly accused business leaders, labor, the news media and even Roman Catholic Church leaders of conspiring to unseat him.

The Venezuelan armed forces have traditionally had strong ties to the U.S. military, and resented Chavez's distancing of Venezuela from Washington. Many also took issue with the president's ties with leftist Colombian guerrillas and with Fidel Castro's Cuba, as numerous senior officers had fought against Cuban-backed communist guerrillas in the 1960s and early 1970s.

Police warned Friday that backers of the president, known as "Chavistas," were reportedly handing out weapons, especially in the hillside slums surrounding the capital, where Chavez has long had strong support among the poor. Officers seized dozens of firearms in raids of storehouses.

Executives at Venezuela's state oil monopoly were jubilant over Chavez's ouster and promised to bring production up to speed as quickly as possible after being engaged in a work slowdown. Venezuela is fourth biggest oil exporter in the world and the No. 3 supplier of oil to the United States.

Upon news of Chavez's downfall, expectations of a production increase drove oil prices down. Oil markets have been concerned over supply after Iraq's decision this week to suspend exports to allies of Israel.

Pedro Carmona, head of Venezuela's largest business association, announced he would head a transitional government to be installed later Friday.

Chavez was being held at the army base while investigators decide what charges could be brought against him for Thursday's violence, said army commander Gen. Efrain Vasquez Velasco. Chavez asked to be allowed to go into exile in Cuba, but the military rejected his offer, army Gen. Roman Fuemayor told Globovision television. "He has to be held accountable to his country," Fuemayor said.

In downtown Caracas, streets were littered with debris – and in some places, stained with blood. After a night when thousands went out and celebrated, shops and businesses remained closed, and most people simply stayed home, stunned and wondering what would come next. Buses were half-empty, and those reporting to work hurried amidst rubble-strewn sidewalks.

"I urge Venezuelans to maintain calm, to keep faith, to continue working on the road toward democracy, freedom and peace," said retired Gen. Guaicaipuro Lameda, who until February headed the oil company and was a leader of the movement to oust Chavez. "It's with sadness that to reach this point, so many people had to die, so many wounded."

The Bush administration said it was closely monitoring the upheaval in Venezuela. "Our interests are in democracy and democratic institutions," said a senior U.S. official traveling with Secretary of State Colin Powell in Jerusalem.

In London, Brent crude oil opened 44 cents down from Thursday at $24.60 per barrel. In New York, May contracts of light sweet U.S. crude fell 46 cents a barrel to $24.53.

Cuba, whose leader Castro is a personal friend of Chavez, denounced the Venezuelan's overthrow, with the Communist Party daily Granma saying it was the result of a "conspiracy" by the country's wealthy classes, corrupt politicians and news media.

The rapid developments stunned this oil-rich, yet poverty-stricken nation.

The demonstration in Caracas late Thursday was the culmination of a strike called by the 1 million-member Venezuelan Workers Confederation and the business association Fedecamaras. The strike was in support of the protesting executives at the state oil company, Petroleos de Venezuela.

National Guard troops fired tear gas at the front ranks of marchers bearing sticks and throwing rocks. Tear gas drifted into the presidential compound. Rooftop snipers and Chavez supporters repeatedly fired upon the protesters and even ambulance crews trying to evacuate the wounded. As many as 110 people were wounded, Greater Caracas Mayor Alfredo Pena said.

As the bloodbath unfolded, Chavez ordered five Caracas television stations off the air.

The wave of protests marked the end for a president whose rule had been a stormy one.

Chavez had irritated Washington with his close ties to Castro, visits to Iraqi leader Saddam Hussein and to Libya, and criticism of U.S. bombings in Afghanistan.

And he had alienated virtually every sector of Venezuelan society, with his attacks on the news media and Roman Catholic Church leaders, his refusal to consult with business leaders, and his failed attempt to assert control over labor groups.

Chavez's government also inherited a staggering $21 billion in back wages and pensions owed workers by previous administrations – a debt he was unable to pay.

His suspected ties to Colombia's leftist guerrillas angered many in the military and abroad.

Domestic opponents claimed his government was secretly arming neighborhood block committees known as "Bolivarian Circles," named after South American liberator Simon Bolivar, to defend his revolution. The Circles were created after Castro urged Chavez's supporters to organize during a 2000 visit.

For Chavez, who on Tuesday boasted he would remain president until 2021, the end came quickly.

Just last Friday, he refused to negotiate with the striking oil executives, who were demanding that he remove a company board he had appointed Feb. 25. The executives claimed Chavez was trying to strengthen his hold on a multinational corporation that cherishes its autonomy.

The executives' slowdown cut production at the Paraguana refinery complex, one of the world's largest, to below 50 percent capacity. They closed another refinery and all but stopped loading of oil tankers. Oil generates 80 percent of Venezuela's foreign earnings.

The Air Force chief, Gen. Regulo Anselmi, said the military urged Chavez on Wednesday to negotiate. He agreed, but by then the oil executives had rejected such overtures.

After Thursday's violence, the high command decided Chavez had to go, and they confronted him en masse in his offices, Anselmi said. Troops seized the government television station as tanks rumbled on the streets.

Chavez finally handed his resignation to Anselmi, Armed Forces Inspector General Gen. Lucas Rincon Romero and National Guard commander Gen. Belisario Landis.

"We ask the Venezuelan people's forgiveness for today's events," said Vasquez Velasco, the army commander. "Mr. President, I was loyal to the end, but today's deaths cannot be tolerated."

The Associated Press contributed to this report.