US Deputy Secretary of State, John Negroponte

"He has been trying to export his kind of radical populism and I think that his behaviour is threatening to democracies in the region," Negroponte told the Senate Foreign Relations Committee.

"I do not think he has been a constructive force in the hemisphere," said Negroponte, currently the US spy chief, at a hearing to confirm his appointment as deputy to Secretary of State Condoleezza Rice.

Long a thorn in the US side, Chavez last week threatened to kick out US Ambassador William Brownfield for criticising his proposals to nationalise key telecommunications and energy industries.

Reelected to a new six-year term in office and with his allies controlling Venezuela's unicameral legislature, Chavez earlier this month was granted the power to rule by decree for 18 months by a unanimous vote from lawmakers.

A former ambassador to Mexico and Honduras, Negroponte has often voiced his dislike of Chavez, whom he accused a year ago of seeking closer relations with North Korea and Iran.

Since Chavez first came to power nine years ago, several other leftist or left-leaning governments have been elected in Latin America, including Nicaragua, Ecuador, Bolivia and Chile.

Negroponte attributed the rise of Chavez and other populist regimes in Latin America to a general disappointment with democracy in the region.

"I think that one of the trends that we need to be concerned about is a kind of a frustration among some of the populations of Latin America ... that democracy is not necessarily delivering the kinds of results that people had hoped for," he said.

But he told senators that despite Chavez's influence "by and large, I think that democracy is doing quite well in the hemisphere."

Turning to Colombia, Negroponte told the Senate committee that the US should continue to back President Alvaro Uribe's efforts to stem leftist guerrilla activity.

"The situation in Colombia is a critical one to our interests and I think it's very important that we continue to support the government of Colombia in its efforts to bring that country under control and to finally put an end to the guerilla activity that's taking place in that country," Negroponte said.

In October, Under Secretary of State for Political Affairs Nicolas Burns said Washington would ask Congress to extend for another two years the 600 million dollars US support for Uribe's Plan Colombia against drug trafficking and guerrilla warfare.