The U.S. government has rejected charges from Venezuela's acting leader that former U.S. officials are planning to assassinate opposition presidential candidate Henrique Capriles and foment a coup.

State Department spokeswoman Victoria Nuland told reporters Monday "the United States categorically rejects allegations of any U.S. government involvement in any plot to destabilize the Venezuelan government or to harm anyone in Venezuela."

Maduro first made the accusation last week and has repeated it since then. He is running against Capriles in an April 14 vote to replace the late Hugo Chavez.

Maduro made the charge again Monday, saying the U.S. was trying to destabilize the country. He said the masterminds were former U.S. diplomats from the administration of President George W. Bush. Maduro asked President Barack Obama to "stop this insanity."