The head of the UN nuclear watchdog agency will to go to Iran next week to try and wrest concessions from Tehran on its atomic programme, diplomats and officials said on Friday.

Mohamed ElBaradei, the head of the IAEA “expects to get positive results” from his trip, said a senior IAEA official. The timing of the planned visit is important. It will occur only about two weeks before ElBaradei is to report to the Security Council on whether Iran has heeded a Council call to reimpose a freeze on uranium enrichment and fully open its nuclear programme to an IAEA probe.

Those requests were contained in a March 29 Council statement that also called on ElBaradei to report back both to his own agency and to the Council in 30 days on whether Iran was complying.

If ElBaradei comes back without meaningful concessions from Iran, the US, France and Britain will be strengthened in seeking forceful Council action. But if Tehran does meet some of the statement’s requests, Russia and China, the two other permanent Council members, will have a stronger case in their arguments that diplomacy and not threats work best with Tehran.