"Nether Bolivia nor Iran nor Venezuela are forming blocs against anyone," Safar Ali Eslamian, Director of the Latin America Department of the Iranian Foreign Ministry, was quoted as saying by Bolivia's newspaper La Razon.

He also defended Iran's nuclear program, saying his country only wants to develop an alternative energy source istead of nuclear weapons.

Bolivian President Evo Morales earlier brushed off concerns about close ties to a country that the U.S. government says is a sponsor of terrorism. Morales said "the international community can rest assured that Bolivia's foreign policy is dedicated to peace with equality and social justice."

Their remarks came after Iranian President Mahmud Ahmadinejad paid visits to Bolivia and Venezuela earlier this week.

Washington has accused Iran of trying to develop nuclear weapons under the cover of a civilian program, seeking tougher sanctions on Iran through the UN Security Council.

Washington has never ruled out military action against Iran to curb Tehran's alleged nuclear programs.

Iran, while strongly denying the US allegations, has insisted that its nuclear program is for peaceful purposes. Tehran has voiced hope for talks to defuse the nuclear standoff with the United States.