"Every Basiji is an atomic bomb, which is why we don't need to make an atomic bomb," General Mohammad Ali Jafari, commander of the elite Revolutionary Guards land forces, told the Hambestegi newspaper.
He also warned the United States and Israel against comsidering attacking Iranian nuclear installations, notably the power plant at Bushehr which is being developed with Russian assistance.
"Such an action by the United States, which is allied to the Zionist regime, would be considered a declaration of war and we would respond," said Jafari, whose country the United States suspects of working to develop nuclear arms.
According to official figures, Iran's Basij force comprises about 10 million men. The force, created in the wake of the 1979 Islamic revolution, is under the command of the Revolutionary Guards.
Also issuing a warning to Israel and the US was deputy Revolutionary Guards commander Mohammad Bagher Zolghadr.
"Any military action (against Bushehr) will receive a crushing response that will be unbearable for the United States and Israel," the general told Siassat Rouz newspaper.
"If Israel committed such an error, it would be signing its own death warrant. With the capacity of the Islamic revolution in Lebanon, Palestine and Iran, and with the power of our armed forces, such an error would be its last," he said.
However the general predicted that as soon as nuclear fuel was stored at Bushehr, no country would dare attack the installation.
Moscow is building the Islamic state's first nuclear power reactor, but says it will not begin delivering nuclear fuel needed to operate the plant until Tehran signs a deal pledging to return the spent material to Russia.
Under pressure from the United States and Israel, Russia has made the return of the spent fuel a key condition for concluding the 800 million dollar (715 million euro) project.