The United States on Tuesday questioned Venezuelan authorities' decision to certify the election of late president Hugo Chavez's heir but condemned the violence during political protests.

The National Election Council's proclamation of President Nicolas Maduro as "the victor before completing a full recount is difficult to understand," State Department spokesman Patrick Ventrell told reporters.

"They did not explain their haste in taking this decision," he said, adding that the United States was not ready to recognize Maduro as the winner.

Ventrell said that the United States supported the right to peaceful protests but condemned the violence, which has left at least seven people dead.

"Violence has no place in a democratic electoral process. So we join in others in calling on all Venezuelans to refrain from violence at this time," Ventrell said.

The United States, which had fraught relations with the leftist firebrand Chavez, had called for a full recount of the election results which showed a narrow victory to Maduro.

Opposition candidate Henrique Capriles has refused to concede defeat and called for protests, although several Latin American powers have recognized Maduro as victorious.

A US official, speaking on condition of anonymity, conceded that Venezuela is unlikely to agree to a recount in the coming days but said that Washington did not want to get ahead of the opposition's decisions.

"The opposition needs some space to be able to express the views of the 50 percent of the people of Venezuela who didn't vote for the guy," the official said.

"I think it would be unusual for us, having been so clear that this recount needed to happen... to suddenly just come out and say 'no problem,'" he said.

Chavez, a strident critic of US policies in Latin America, accused the United States of involvement in a 2002 coup in which he was briefly overthrown.