Barack Obama in Chicago
Barack Obama in ChicagoReuters

US President Barack Obama recently sent a private message to the Iranian leadership via Iraq's prime minister, as pressure mounts for the sides to reach a deal over Tehran's nuclear program by June 30.

With just one day to go before the deadline, Iran's Hamshahri daily claims that "one of the leaders of a neighboring country" took the message from Obama to officials in Tehran, according to AFP.

The paper went on to suggest that the leader in question was Iraqi Prime Minister Haider al-Abadi, who met Obama at the G7 summit in Germany on June 8, and visited Tehran just over a week later, where he met Iranian supreme leader Ayatollah Ali Khamenei and President Hasan Rouhani.

"Officials at the Foreign Ministry, including an informed source on the ministry's Iraq desk, said they did not have any knowledge" of such a message, the paper said, and also mentioned Abadi's visit to Washington in April to lobby for more military support against ISIS.

Relations between Washington and Tehran have been the focus of great controversy, with critics - most notably Israel and the Gulf Arab states - accusing the White House of conceding far too much in its pursuit of detente with the Islamic Republic.

As tomorrow's deadline looms, pressure on the Obama administration is increasing to reach a deal which would prevent Iran from obtaining nuclear weapons. Last week, an unprecedented open letter from 18 leading foreign policy experts - including five former top Obama administration officials - criticized the Obama administration for negotiating a "bad deal."

A hint to just how "bad" that deal will be may have emerged Sunday, with reports the P5+1 powers had dropped a key - seemingly fundamental - condition, by agreeing that there would be no inspections of sensitive Iranian nuclear sites.