A march to demand a recount in Venezuela's contested presidential election turned violent Tuesday in the home state of the late President Hugo Chavez as the government blamed the opposition candidate for violent disturbances it said had claimed seven lives and left 61 people injured.

In a televised broadcast, Justice Minister Nestor Reverol accused the candidate, Henrique Capriles, of numerous crimes including insurrection and civil disobedience.

Government officials have been alleging since Monday that Capriles is plotting a coup, and President-elect Nicolas Maduro announced that he was prohibiting an opposition march scheduled for Wednesday in the capital.

In Washington, meanwhile, the Obama administration said it was refusing to accept the official results of Sunday's vote without a full recount given the closeness of the result: a margin of 50.8 percent to 49 percent favoring Maduro, the chosen successor of Chavez, who succumbed to cancer last month.

In Chavez's home state of Barinas, police fired tear gas and plastic bullets at protesters heeding the Capriles' call for protests by marching on the provincial headquarters of the National Electoral Council.

Chief prosecutor Luisa Ortega said 135 people had been detained in protests. Opposition leaders reported 30 arrests Tuesday. There were no immediate reports of injuries.

Capriles' supporters also protested in cities including Merida and Maracay;.

In the capital, Caracas, Maduro said he would not permit an opposition march that Capriles called for Wednesday. His chief prosecutor, meanwhile, said seven people had been killed in protests.

Maduro blamed Capriles personally.

“You are responsible for the dead we are mourning,” he said, calling Capriles “the defeated candidate.”

Reverol said one of the dead was a man in the capital who was shot dead by opposition supporters.  He said the other shooting deaths, in the states of Sucre, Tachira and Zulia, were being investigated.

The prosecutor, Ortega, said those killed were humble members of the working class.

Capriles issued a message on Twitter blaming the government that he says stole the election.

“The illegitimate one and his government ordered that there be violence to avoid counting the votes,” he said. “They are responsible!”

Maduro was certified the winner of a presidential election Monday amid questions about his ability to lead after he squandered a double-digit lead in the race despite an outpouring of sympathy for his party following Chavez's death.

On Monday, thousands of students briefly clashed with National Guard troops who fired tear gas and plastic bullets while people across the nation banged on pots and pans to reject the National Electoral Council's ratification of Maduro's victory without a recount.

Late Monday, Maduro announced he had met with a newly created “anti-coup” command at the military museum that holds Chavez's remains.

He accused opposition protesters of attacking government clinics and the house of electoral council President Tibisay Lucena, without offering details.

Government leaders and military leaders have closed ranks around Maduro despite his weak showing Sunday.

But a hint of discontent emerged in two Twitter messages by Diosdado Cabello, the National Assembly president who many consider Maduro's chief rival within the “Chavismo” movement.

He expressed dismay after the electoral council president announced the election results.

In the first, he called for a “profound self-criticism” within Chavista ranks. In the second, he wrote: “We should look for our faults under the rocks if we have to.”

Diego Moya-Ocampos, an analyst with the London-based consulting firm IHS Global Insight, said members of the ruling socialist party “realize that Maduro is not the man to guarantee continuity of the Chavista movement.”

Cabello expressed disbelief at Capriles' strong showing, asking why “sectors of the poor population would vote for their exploiters of old.”

That might not be such a mystery.

Among Venezuela's problems are crumbling infrastructure, persistent shortages of food and medicine, and double-digit inflation. The nonprofit Venezuelan Violence Observatory estimates Venezuela's homicide rate last year was 73 per 100,000 people, among the world's worst.

With such a narrow victory, Maduro has little political capital to make the difficult choices some of those problems require, said Risa Grais-Targow, Latin America analyst for the Eurasia Group.

Price and currency controls imposed under Chavez have failed to stem inflation or the flight of dollars and are strangling private firms. But lifting them abruptly could bring economic turmoil and hurt the poor.

Grais-Targow said Maduro will likely focus instead on expanding the myriad of social programs that cemented Chavez's popularity. But that has become increasingly difficult to balance with the need to spend on redressing Venezuela's other problems.

The state-oil company that gave billions of dollars to fund social programs is saddled with mounting debt and declining profits. Critics say the company has failed to invest in boosting oil production, which has fallen for years even though Venezuela has the world's biggest oil reserves.

Throughout the campaign, Maduro blamed Venezuela's frequent power blackouts on sabotage by government enemies and said food shortages are caused by hoarding by the private sector. So did Chavez before he died, but Sunday's election results showed that a growing numbers of Venezuelans are no longer buying it.

Maduro, a former bus driver who rose to become foreign minister and vice president under Chavez, offered no ideas of his own for resolving the country's problems. He did suggest at the news conference Monday night that a Cabinet shake-up was in the works, though he quickly added that he would ratify Vice President Jorge Arreaza, Chavez's son-in-law, in his post.

Chavez swiftly sidelined those who openly questioned him during his 14 years in power.

Maduro's narrow victory has given him less ability to maintain unity in a movement held together largely by loyalty to the charismatic Chavez.

Its factions include former soldiers like Cabello who joined Chavez in a failed 1992 coup. Maduro comes from the ranks of leftist political and labor groups that united to help elect Chavez president in 1998. Chavez's relatives, led by his brother Adan, form another bloc.

“His legitimacy comes from the fact that Chavez named him as his successor and other factions were forced to accept it,” said Grais-Targow. “But he faces this landscape where the other main figure, Diosdado Cabello, could elevate his role and have more power. There are also governors who have bases of support and could pose challenges.”

Still, the powerful state political apparatus built by Chavez is standing with Maduro.

Four of the five directors of The National Electoral Council are pro-government. The Supreme Court is stacked with Chavista sympathizers, as are inferior courts. The National Assembly is also controlled by Chavistas. (AP)