Iran declared a day of national mourning on Wednesday after the death of Venezuelan President Hugo Chavez, who shared the Islamic Republic's loathing for US "imperialism".
Iranian President Mahmoud Ahmadinejad, who had forged a public friendship with Chavez characterised by lavish mutual praise, hugs and light-hearted moments, may attend Chavez's funeral on Friday, state news agency IRNA reported.
The two men had sought closer ties between their geographically distant countries, although action on joint social and military projects announced in recent years has often lagged behind the rhetoric.
"Hugo Chavez is a name known to all nations. His name is a reminder of cleanliness and kindness, bravery ... dedication and tireless efforts to serve the people, especially the poor and those scarred by colonialism and imperialism," Ahmadinejad said.
"I offer my condolences to all nations, the great nation of Venezuela and his respected family over this tragic event," he said in statement published on his official website.
Chavez died on Tuesday after a two-year battle with cancer. He suffered multiple complications after his latest operation in December and had not made a public appearance since.
The news of Chavez's death dominated many Iranian news websites, which carried obituaries and photo galleries of him.
The United States had looked askance at Venezuela's warm relationship with Iran, fearing that Caracas could give Tehran an economic lifeline as it struggles to stave off pressure from sanctions over its nuclear activities.
Iran denies seeking an atomic weapons capability and says it has the right to develop its own nuclear fuel cycle under its membership of the nuclear Non-Proliferation Treaty.
Chavez, at a news conference with Ahmadinejad in Caracas in January 2012, mocked U.S. suspicions about Iran's nuclear work, saying: "That hill will open up and a big atomic bomb will come out."