President Hugo Chavez said on Sunday that his government is redoubling efforts to detect assassination plots, calling US diplomat John Negroponte a "professional killer" and saying he believes enemies - including the CIA - are out to kill him.

Chavez said Venezuelan officials have intelligence that associates of jailed Cuban anti-communist militant Luis Posada Carriles also are involved in plotting to assassinate him.

He said the death plot idea has "gained weight" due to various factors, including the recent appointment of Negroponte, the former director of national intelligence, as deputy to US Secretary of State Condoleezza Rice.

"Who did they swear in ... there at the White House as deputy secretary of state? A professional killer: John Negroponte," Chavez said.

Chavez's government has accused Negroponte of playing a key role in the Contra war against the leftist Sandinista government of Nicaragua when he served as US ambassador to Honduras - a haven for clandestine Contra bases - from 1981 to 1985.