EXCLUSIVE: Iran and the international community are getting ready for a new round of talks next month aimed at resolving questions surrounding the Islamic Republic’s suspected nuclear program.

In exclusive interviews with two of the main players in the dispute, Fox News learned firsthand of the hardened differences that remain on this potentially life-and-death matter.

Yukiya Amano, head of the International Atomic Energy Agency, the U.N.’s Vienna-based nuclear watchdog, says he thinks Iran at the very least is preparing for the possibility of building a nuclear bomb.

“We have information that indicates Iran was engaged in activities relevant to the development of nuclear explosive devices,” Amano told Fox News.

But Iran’s longtime ambassador to the IAEA, Ali Asghar Soltanieh, denies this, telling Fox News that Iran “…has not been pursuing a nuclear weapon” and that his country’s nuclear program is aimed only at “peaceful purposes.”

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Soltanieh said Iran “will never, ever suspend our activities, including enrichment” of uranium, which is demanded in U.N. Security Council resolutions and is expected to be on the table in next month’s talks.

The possible weaponization of Iran’s nuclear program will be another key talking point in negotiations. Amano raised questions about Iran’s Parchin military facility, where a high explosive chamber allegedly exists and has been used to test a detonation device for a nuclear bomb.

The IAEA was refused access to the Parchin facility during a visit to Iran last month.

“We would like to go there and examine if that is the case or not,” Amano said.

Soltanieh claimed Iran was prepared to let the IAEA visit the site until the matter became “politicized.” Still, he didn’t sound too welcoming when he referred to the IAEA’s visit to Parchin in 2005.

“We cannot permit each time any country wants to knock at the door and wants to go to our military sites,” he said.

Soltanieh denied that ever-tightening and crippling international sanctions are forcing Iran closer to making concessions.

“Sanctions have had no effect,” he said. “We are more determined to pursue our nuclear activities.”

And he brushed off the growing threat of an Israeli attack on nuclear sites in Iran, saying, “Nobody would dare attack Iran.”

If Israel did attack, he said ominously, there would be “…a strong response with an ‘iron fist.’”

Amano rejected accusations that he has been overstating the Iranian nuclear threat and that -- unlike his predecessor, Mohammed el-Baradei -- he favors the United States.

“What I do inevitably has political implications, but it doesn’t mean we put political considerations first,” he said. “It should be the opposite; technical considerations should come first.”

And as Iran and the West continue to squabble over the details of next month’s talks, the former Japanese diplomat is careful to warn that the two sides may still be far from a breakthrough.

“It will take time,” he said. “This is a complicated issue with a long history.”

Soltanieh said there’s “a window of opportunity” to resolve the issues, but he hinted it could be on Iran’s terms.

“If you tell the Iranian people you ‘must’ do something, the answer is ‘no’ in a loud voice,” he said. “If you ask Iranians to ‘please’ do something, you will see flexibility and concession.”

The coming weeks could indicate how “polite” both sides plan to be about this possibly lethal issue.

Greg Palkot currently serves as a London-based senior foreign affairs correspondent for Fox News Channel (FNC). He joined the network in 1998 as a correspondent. Follow him on Twitter@GregPalkot.