UN nuclear inspectors have arrived in Tehran for the second time in a month to discuss Iran’s nuclear programme.
Chief inspector Herman Nackaerts said his team’s “highest priority” was to clarify the “possible military dimensions” of the nuclear programme.
But he cautioned that progress “may take a while”.
Iran insists it is enriching uranium to use for power generation, but Western nations believe the programme is geared towards making weapons.
Tensions have risen over speculation that Israel may carry out a military strike on Iran’s nuclear facilities.