As the International Atomic Energy Agency prepares to release its latest report on Iran's nuclear program, an Obama administration official said Thursday that the Islamic regime has a credibility problem.

"Iran, over many years, has been unable to demonstrate the peaceful intent of its nuclear program," Deputy National Security Adviser for Strategic Communications Ben Rhodes told reporters in Cannes, France, where President Obama was attending the G20 summit.

"They're the only treaty member of the (Nuclear Nonproliferation Treaty) that cannot convince the International Atomic Energy Agency that their program is peaceful," Rhodes said.

The U.N. nuclear watchdog is expected to roll out an update next week to bullet point the purpose and size of Iran's nuclear fuel program. The country insists that it is only interested in energy, but the assessment is expected to detail mounting evidence that Iran may be building an atomic bomb.

Rhodes noted that Iran is already ignoring the requirements of the IAEA report, and the NPT.

During Thursday's meetings, Obama stressed the need to maintain "unprecedented international pressure on Iran to meet its obligations."

Those obligations are laid out in a U.N. Security Council sanctions package against Iran, which Rhodes said the U.S. and France aggressively pursued to put pressure on the Iranian government. He said that it has resulted in "the toughest sanctions regime to date," marginalizing Iran globally.

But the isolation is further exacerbating tensions between Tehran and Washington.

"What we're focused on is a diplomatic strategy," said Rhodes, "which increases the pressure on the Iranians, through financial pressure, through economic sanctions, through diplomatic isolation."