Iran's suspected nuclear drive is expected to top the agenda when the UN atomic agency's 35-member board of governors meet this week in Vienna.
The meeting of the International Atomic Energy Agency (IAEA) will be held behind closed doors starting on June 4 and is due to go on all week.
The IAEA is seeking access to Iran's Parchin military base, where it believes suspicious explosives testing has recently been carried out.
Tehran has denied access to the base, arguing the site was not linked to its nuclear program.
Iran and the P5+1 powers -- the United States, Russia, China, Britain, France, and Germany -- met in Baghdad in May in a bid to ease tensions over Tehran's suspected nuclear drive, but little was achieved.
A further meeting is set in Moscow for June 18-19.
WIth reporting by AFP