On Wednesday the IAEA issued a critical report that said Iran had expanded its uranium enrichment programme in defiance of UN demands for its suspension, and warned that the watchdog's knowledge of Iran's activities was shrinking.
The Islamic Republic denies seeking nuclear weapons, saying its programme is a purely civilian one designed to generate electricity.
ElBaradei said the IAEA had seen no evidence that Iran was trying to "weaponise" nuclear material.
However, he said Tehran was continuing to move towards confrontation with other world powers by accelerating its nuclear programme despite calls by the Security Council for it to suspend uranium enrichment.
"Iran has a right to pursue nuclear power but it should abide by international agreements and laws"
David, NYC, US
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But on Thursday, in a speech to a gathering of Iran's Revolutionary Guards, Mahmoud Ahmadinejad, the Iranian president, ruled out the possibility of a suspension of the country's nuclear programme.
"The enemy wants Iran to surrender so it won't have any say in the world," he said, according to state-run television.
"The aim of the enemies in thwarting Iran's exploitation of peaceful nuclear technology, is not based on any technical reasons. They want to hit at the source of the [Iranian] regime's progress.
"If Iran's right to nuclear technology is confirmed, all nations of the world will gather under Iran's political banner. The enemies of Islamic Iran know this, and for this reason they have mobilised."
The US has urged new sanctions against Iran, in addition to the two sets of measures agreed on by the UN Security Council in December and March.
The US president, George Bush, said on Thursday that the UN should strengthen sanctions against Iran over its defiance of international pressure to curb its nuclear programme.
"My view is that we need to strengthen our sanctions regime," Bush told a news conference in Washington.
|Bush said he would discuss the Iran nuclear
issue with Russian and Chinese leaders [AFP]
"I just spoke to Condoleezza Rice [the US secretary of state], and we will work with our European partners to develop further sanctions.
"And, of course, I will discuss this issue with [Russian President] Vladimir Putin, as well as [Chinese] President Hu Jintao.
"The first thing that these leaders have got to understand is that an Iran with a nuclear weapon would be incredibly destabilising for the world.
"It's in their interests that we work collaboratively to continue to isolate that regime."
Bush also called it "unacceptable" that Iranian authorities had recently detained several Iranian-Americans in Iran and said Washington had made its position clear to Tehran.
Earlier on Thursday, Bernard Kouchner, the French foreign minister, said Paris backs the rapid adoption of "new sanctions" against Iran if it maintains its refusal to suspend uranium enrichment.
He said in a statement released in Paris: "There is still time for Iran to suspend its enrichment-linked activities.
"Otherwise, as foreseen by Resolution 1747, we will have no choice but to take things forward at the Security Council."