Six major powers are seeking to negotiate an agreement under which Iran would limit its nuclear program in exchange for the easing of economic sanctions that have crippled its economy.

Envoys from Britain, France and Germany, three of the so-called P5+1 group that includes China, Russia and the United States, sketched out their expectations for the end game as a self-imposed June 30 approaches.

“It’s very likely that we won’t have an agreement before the end of June or even (right) after,” French ambassador to the United States Gerard Araud said in an appearance at the Atlantic Council think tank with his British and German counterparts.

The Iranians want to force the six powers’ ministers to decide the issues, rather than lower-level officials, Araud said, saying he expected some melodrama toward the end with late nights and doors slammed as both sides jockey for the best deal.

“Even if we get the best deal … afterwards, you will have to translate it into the technical annexes, so it may be … we could have a sort of fuzzy end to the negotiation,” he said.

Speaking after the event, Araud said it could take a few weeks of July to complete the technical annexes that are envisaged under an agreement if one can be reached.

Iran and the six powers reached a framework agreement on April 2, but several issues remain unresolved, including the pace of sanctions relief and the monitoring and verification measures to ensure Iran does not pursue a clandestine nuclear program.

Iranian officials have said they must receive sanctions relief immediately upon reaching an agreement. Western officials have argued that sanctions will be eased gradually and only after Iran has taken steps to limit its nuclear program.

“Iran needs some time to start the implementation of this agreement, so in the best case sanctions relief would not happen before the end of this year,” German ambassador to the United States Peter Wittig said.