By Daniel Wallis and Andrew Cawthorne
CARACAS, March 13 (Reuters) - Venezuela's acting president said on Wednesday that "far right" figures in the United States were plotting to kill opposition leader Henrique Capriles in an increasingly volatile atmosphere ahead of an April 14 election.
Accusations are flying and emotions are running high in the South American OPEC nation of 29 million people since the death last week of former socialist leader Hugo Chavez.
"We have detected plans by the far right, linked to the groups of (former Bush administration officials) Roger Noriega and Otto Reich, to make an attempt against the opposition presidential candidate," Nicolas Maduro said.
He gave no more details, but said in a televised speech that the government had sent a senior general to meet with aides of Capriles. There was no immediate response from Washington or Capriles' camp.
During the Chavez era, there were frequent claims of U.S. plots aimed at discrediting his self-styled revolution. Critics said they were a smokescreen to create a sense of "imperialist" threat and distract Venezuelans from daily problems.
Why foreign right-wingers would want to bring down the business-friendly Capriles was not explained by Maduro.
The upcoming vote will pit Maduro, Chavez's heir apparent, against Capriles, a centrist state governor who lost an election to Chavez in October.
Noriega, a former Assistant Secretary of State for Latin America under former president George W. Bush, denied Maduro's accusation. "Its absolute nonsense," said Noriega said.
"They call you what they are and they accuse you of doing what they do. That is the way they operate," Noreiga.
Reich was not immediately available to comment.
Earlier this week, Capriles' team said the opposition candidate had not registered his candidacy in person on Monday because they had received information that an attack against him was planned. Aides delivered his papers instead.
In January, Maduro said unidentified groups had entered the country with the aim of assassinating him and the head of the National Assembly, Diosdado Cabello.
This week, Maduro also said Venezuela will set up a formal inquiry into claims that Chavez's cancer was the result of poisoning by his enemies abroad.
Venezuela's acrimonious election campaign was further stirred by remarks from Maduro that were widely perceived as a homophobic slur against Capriles.
Capriles, 40, was the target of racial and sexual innuendoes by Chavez's supporters throughout last year's presidential race: one cartoon shown on state media depicted him in pink shorts with a Nazi swastika on one arm.
Chavez himself was also vilified by foes as an uncouth clown throughout his rule. The mockery included racist insults and photos of apes with his face superimposed.
Denigrating images of Maduro driving a bus - his former job - are now circulating among anti-government factions.
In the flurry of back-and-forth accusations from both camps this week, Maduro appeared to revive last year's line of attack over Capriles' sexuality. Capriles is unmarried.
"I do have a wife, you know? I do like women!" Maduro told a rally. He has also called Capriles "a little princess."
The comment drew hoots of laughter from supporters, some shouting explicit insults against the opposition leader.
That infuriated backers of Capriles, whom polls show has an uphill struggle to beat Maduro. "I believe in a society where no one feels excluded due to their way of thinking, race, beliefs or sexual orientation," Capriles said in response.
Images of guns pointed at TVs showing Capriles' image are also doing the rounds, triggering a formal opposition complaint.
On Wednesday, Maduro rowed back and insisted he was always respectful of others' private lives. "If I were homosexual I would be proud about it and I would love whoever I loved with my heart, without problem," he said.
Venezuela's acting leader also said on Wednesday that plans to embalm Chavez's remains, in the style of Communist leaders Lenin, Stalin and Mao, had run into problems.
"Russian and German scientists have arrived to embalm Chavez and they tell us it's very difficult because the process should have started earlier. ... Maybe we can't do it," he said. (Additional reporting by Ana Isabel Martinez, Mario Naranjo and Patricia Velez)