Caracas and Tehran have a responsibility to stand together against Washington and its allies, Chavez said with Iran's Mahmoud Ahmadinejad at his side at Caracas' lavish Miraflores presidential palace.
"We didn't ask for this task, but it's our duty to stop the crazed imperialism that is stronger than ever before," he said a day before the two leaders were to fly Tuesday to Nicaragua for the swearing-in ceremony of Chavez ally and former Sandinista leader Daniel Ortega for his second presidential term.
"It's a danger to the world, these pretensions of the Yankee empire to control the globe," Chavez said.
His comments came a day after Washington expelled the Venezuelan consul general in Miami over an alleged plot among Venezuelan, Iranian and Cuban diplomats to start a cyberattack against Washington.
The U.S. State Department said it gave Livia Acosta Noguera until Tuesday to leave the country after declaring her "persona non grata," the most serious form of censure a country can apply to a foreign diplomat, who is otherwise protected by diplomatic immunity from arrest and other normal kinds of prosecution.
Department spokeswoman Victoria Nuland said Monday she could not provide details about the decision, "but I will tell you that we do not take it lightly when we declare somebody persona non grata."
Venezuela said it would respond "forcefully" but had taken no action as of early Tuesday.
Acosta was allegedly involved four years ago in plans, with a group of Venezuelan, Iranian and Cuban diplomats, then based in Mexico, to attack the computer systems of the White House, FBI, CIA, Pentagon, National Security Agency and several nuclear power plants, the U.S.-based Spanish-language TV network Univision reported.
The International Atomic Energy Agency Monday accused Iran of beginning uranium enrichment at the fortified underground Fordow Enrichment Plant near the Iranian holy city of Qom, and Iran's Revolutionary Court sentenced a 28-year-old former U.S. Marine to death on charges of spying for the CIA.
The State Department called the alleged uranium enrichment a "further escalation" of Iran's "ongoing violations" of U.N. resolutions. It also denied Arizona-born Amir Mirzaei Hekmati, a former U.S. military translator with dual nationality, was a spy, and demanded his immediate release.
Ahmadinejad said Monday in Caracas his nation was prepared for "martyrdom" against the United States and its allies but had no aggressive intentions.
"We love everyone, including the people of the United States who are suffering under the domination of the arrogant," he said.
Chavez said the United States and its "lackeys" sought to paint Iran and Venezuela as aggressors.
"They say that we are going to go into the basement of Miraflores and come out with a cannon with missiles because we are going to attack Washington. ... That's practically what they're saying," he said.
Chavez, a former career army officer said the two leaders were arming themselves for a conflict but the war was "against poverty, against misery, against hunger, against underdevelopment. That is our war."
Ahmadinejad said if Iran and Venezuela were jointly building anything like a bomb, "the fuel of that bomb is love."
Ahmadinejad is in Latin America to shore up support from regional leftist leaders as tough new Western sanctions seek to isolate the Islamic republic and target its vital oil exports. He was also to visit Cuba and Ecuador.
All the nations on Ahmadinejad's itinerary have governments opposed to U.S. regional influence.