Venezuela ? A U.S. official on Friday denied claims by President Hugo Chavez that Washington masterminded an opposition boycott of this weekend’s elections and was trying to foment an overthrow of his leftist government.

The South American country’s two biggest opposition parties also denied any U.S. links to the election protest.

Chavez accused President Bush late Thursday of being behind the withdrawal of major opposition parties from Sunday’s congressional elections, saying he had proof the CIA was “encouraging this new conspiracy.” He provided no details.

“The decisions made by the political parties were their decisions alone,” U.S. Embassy spokesman Brian Penn said. “We are simply not responsible for everything that goes on in Venezuela.”

Chavez said Friday that seizures by federal authorities of C-4 explosives, molotov cocktails and “other materials for provoking violence” during raids in central and western Venezuela were proof of the plan for “electoral sabotage” He did not elaborate.