The US vice-president says a great deal of progress has been made after the first round of talks between the US and Iran.

Pickaxe Mountain, a secret nuclear site in the Zagros Mountains, shows continued construction per satellite imagery. IAEA inspectors have not been allowed to visit the facility.

The IAEA chief acknowledged contradictory remarks between Iran and the U.S. on the subject, calling it a “war of words” at the moment.

The U.N. atomic watchdog’s board on Wednesday demanded that Iran fully cooperate with the agency, provide complete information about its stockpile of near weapons-grade nuclear material and grant its inspectors access to Iranian nuclear sites.

President Donald Trump said Thursday that only the U.S. and China can retrieve enriched uranium from Iran’s buried nuclear sites following strikes last year. The U.S. and Tehran continue to work toward a deal to end the war.

The air campaign across Iran damaged some of its most famous monuments, shattering glass and wood, and cracking walls and ceilings at UNESCO sites.