The U.N. nuclear agency chief on Monday announced new talks with Iran and urged it to sign a deal that would relaunch his long-stalled probe into suspicions that Tehran worked secretly on atomic arms.

For the first time, International Atomic Energy Agency head Yukiya Amano also said that Iran had demolished buildings and carried out other activities at a military facility that his agency believes was a site for such work.

Diplomats and officials accredited to the IAEA had spoken of similar work previously, describing it as an apparent attempt to clear the site of evidence of clandestine weapons-related work but confirmation by Amano lent weight to the suspicions.

Amano did not specify the focus of upcoming talks on Friday between officials from his agency and a senior Iranian envoy. But in the context of his remarks it was clear that IAEA negotiators would press Iranian officials to finalize an agreement on restarting his agency's investigation after a more than four-year pause.