Venezuelan opposition candidate Henrique Capriles -- believed to be the target of an alleged assassination plot by the U.S. government.

He kicked off his election campaign last weekend ahead of the country's April 14 vote following the death of former President Hugo Chavez.

But acting President Nicolas Maduro, Chavez's preferred successor as president, says the U.S. is behind a plot to assassinate Capriles-- to sow chaos in the state and trigger a coup.

In an interview on Sunday, he called on President Barack Obama to stop the alleged plan, laying the blame on former Bush administration officials Roger Noriega and Otto Reich.

Both rejected the claim as untrue, outrageous and defamatory.

During his 14 years in power, Chavez often denounced U.S. plots against him and his revolution.

Critics dismissed those claims as a smokescreen to keep voters focused on a sense of imperialist threat.

Capriles has said Maduro would be to blame if anything happen