President Barack Obama on Tuesday said the United States was interested in a "constructive" future relationship with Venezuela after the death of President Hugo Chavez, a long-time American foe.

Chavez earlier lost his battle with cancer, which silenced the leading voice of the Latin American left and plunged his divided oil-rich nation into an uncertain future.

"At this challenging time of President Hugo Chavez's passing, the United States reaffirms its support for the Venezuelan people and its interest in developing a constructive relationship with the Venezuelan government," Obama said.

"As Venezuela begins a new chapter in its history, the United States remains committed to policies that promote democratic principles, the rule of law, and respect for human rights," he said in a short written statement.

Earlier, Washington rejected Venezuela's allegations that it was involved in a conspiracy over Chavez, saying claims in Caracas that the United States was somehow behind his cancer were "absurd."

The Pentagon confirmed the expulsion of two Air Force officers from the US embassy in Caracas while the State Department condemned allegations of a plot to undermine Venezuela.

The expulsions were announced after Vice President Nicolas Maduro had accused the country's "historic enemies" of causing Chavez's cancer.

Maduro alleged the expelled US military officers had been seeking out active Venezuelan military officials to obtain information about the armed forces and propose "destabilization projects."