El-Baradei estimated that once Iran's mothballed Natanz underground enrichment plant becomes operational, Iranians could be "a few months" away from a nuclear weapon.
International Atomic Energy Agency officials have said that it would take at least two years for the facility to become fully operational.
In an interview to the British newspaper Independent, El-Baradei added that the international community is concerned about Iran "because lots of people feel it could be a dual purpose program."
"It's difficult to read their intention. We're still going through the program to make sure it's all for peaceful purposes," he said.
"I know they are trying to acquire the full fuel cycle. I know that acquiring the full fuel cycle means that a country is months away from nuclear weapons, and that applies to Iran and everybody else," he added.
In the interview, ElBaradei appealed to both Iran and the West to refrain from escalating their dangerous game of brinkmanship, which has entered an unpredictable phase after the election of a hardline Iranian president.
'Everybody would be hurt'
Talks between Iran and the European Union, which has been leading negotiations aimed at preventing the Iranians from building a nuclear bomb, broke down in August, when the Iranians resumed nuclear-related activities at their Isfahan plant.
El-Baradei said he could see no victors from an escalation. "Everybody would be hurt," he said, referring to all parties in the dispute.
"You would then open a Pandora's box. There would be efforts to isolate Iran; Iran would retaliate; and at the end of the day you have to go back to the negotiating table to find the solution," he added.
On Sunday, the head of Tehran's National Security and Foreign Policy Commission Alaeddin Boroujerdi was quoted as saying Iran's Atomic Energy Organization has been given license to set up another 20 nuclear plants.
Intelligence officials in Israel and in the world expressed their concerns that the plan is not for peaceful purposes, but rather for uranium enrichment in order to equip Iran with nuclear weapons.
Last week, Prime Minister Ariel Sharon said that "Israel, and other countries, cannot accept a situation where Iran has nuclear arms. The issue is clear to us and we are making all the necessary preparations to handle a situation of this kind."