International Atomic Energy Agency (IAEA) head Rafael Grossi warned on Monday of a wave of nuclear proliferation if Iran builds a nuclear weapon.
"Many countries have said that if Iran gets a nuclear weapon, they will do the same. I think we have heard it very clearly from many countries," Grossi said on the sidelines of an IAEA conference in Vienna.
"We have to avoid an aggravation of the erosion of the non-proliferation regime. This is very important, and I think my Iranian counterparts know it. I think adding nuclear weapons to the cauldron of the Middle East is a very bad idea," he said.
Grossi called for cooperation with Iran to try to prevent this. He called on Iran to show greater transparency on its nuclear programme and noted that Saudi Arabia had indicated that it would react accordingly to an Iranian nuclear weapon.
While official Iranian policy does not provide for acquiring a nuclear weapon, several representatives have recently raised concerns with comments on a possible change to this doctrine and on Iran's capabilities with respect to building a nuclear weapon.
Grossi has repeatedly noted that Iran is enriching uranium to near-weapons level.
Germany, France and the United Kingdom have worked to draft a possible resolution to be put to the IAEA board of governors' meeting this week that would react to Tehran's failure to cooperate with IAEA inspectors.
Iran has denied access to experienced inspectors and is not providing information on formerly secret nuclear plants where traces of nuclear material were found.