Venezuela's President Hugo Chavez can work towards better ties with the US by avoiding inflammatory rhetoric, the US State Department has said.
President Chavez celebrated triumphantly before supporters
Deputy Secretary of State Richard Armitage made the remarks at a ceremony to swear in a new US envoy for Caracas.
President Chavez meanwhile celebrated a referendum victory endorsing his rule by criticising the opposition groups that had campaigned against him.
He has previously accused the US of financing the opposition.
At a ceremony to swear in William Brownfield as the new US ambassador to Venezuela, Mr Armitage said he hoped Caracas would co-operate on measures to counter the drug trade and terrorism.
Dealings between the two countries could improve if the Venezuelan government considered "how its actions - and its rhetoric - might affect the future of our bilateral relations", he said.
The US has tended to avoid direct criticism of President Chavez, whose country is a major oil supplier.
The president, a former commando with a strong following amongst the poor, won a referendum on his rule earlier this month by a sizeable margin.
'Don't be a liar'
The US envoy to the Organisation of American States (OAS), one of the bodies whose observers ratified the referendum, gave a guarded welcome to President Chavez's victory.
John Maisto said on Friday that the referendum did not mark the end of the "quest for Venezuelan democracy".
He urged President Chavez to safeguard the rights of the opposition, which has contested the result of the referendum with accusations of electoral fraud.
Addressing his supporters in Caracas on Friday, the Venezuelan leader attacked OAS' Secretary-General, Cesar Gaviria, who had earlier alleged pro-Chavez bias amongst electoral officials.
"I say to Dr Gaviria, don't be a liar... It wasn't like that," he said.
He also accused opposition leaders of being "terrorists, coup-plotters and counter-revolutionaries" for questioning the referendum result.
"We don't care if a bunch of desperate people are still running around shouting about fraud," Mr Chavez said.