Iran does not intend to enrich uranium above the 20 percent level, the chief of Iran's nuclear program told the country's media outlets on Monday, adding that Iran increased its enrichment activities after failing to obtain uranium for its Tehran research facility.

The comments by Head of the Atomic Energy Organization of Iran Fereydoun Abbasi came after the Iranian nuclear chief said earlier Monday that that "terrorists and saboteurs" might have infiltrated the International Atomic Energy Agency in an effort to derail his country's nuclear program.

"Terrorists and saboteurs might have intruded the agency and might be making decisions covertly," Abbasi said at the annual member state gathering of the IAEA, alleging that explosives had been used to cut power lines from the city of Qom to the Fordo underground uranium enrichment plant on August 17.

A day later, he said, IAEA inspectors had asked for an unannounced visit to Fordo.

"Does this visit have any connection to that detonation? Who other than the IAEA inspectors can have access to the complex in such a short time?" Abbasi-Davani told the gathering in Vienna.

"It should be recalled that power cut-off is one of the ways to break down centrifuge machines," he said, referring to the machines used to enrich uranium, which can have both civilian and military purposes.

On Tuesday, both state-run Press TV and Iran's official news agency IRNA cited Abbasi as saying of Monday's meeting that Tehran's goal wasn't to enrich uranium beyond 20 percent.

Speaking to reporters, the AOEI chief said that the only reasons Tehran upgraded its uranium to 20 percent was because it failed to obtain uranium for its Tehran Research Reactor, adding that most of Iran's enrichment activities were conducted at the 3.5 percent level.

Rejecting claims that Iran was using its civilian reactors to hide a nuclear weapons program, Abbasi said that the purpose of the enriched uranium was to produce radiopharmaceuticals.

On Sunday, Prime Minister Benjamin Netanyahu warned that Iran would be on the brink of nuclear weapons capability in six to seven months, adding new urgency to his demand that President Barack Obama set a clear "red line" for Tehran in what could deepen the worst U.S.-Israeli rift in decades.

Taking his case to the American public, Netanyahu said in U.S. television interviews that by mid-2013, Iran would be 90 percent of the way toward enough enriched uranium for a bomb. He urged the United States to spell out limits that Tehran must not cross or else face military action - something Obama has refused to do.

"You have to place that red line before them now, before it's too late," Netanyahu told NBC's "Meet the Press" program, saying that such a U.S. move could reduce the chances of having to attack Iran's nuclear sites.