In December, President Barack Obama said he believed the odds that negotiation with Iran over the dismantling of their nuclear program would be successful were no better than 50-50. He got that half right.

With the P5+1 talks in Vienna over a potential nuclear accord with Iran resuming just last week, Iran’s Supreme Leader Ayatollah Ali Khamenei published his country’s latest demand on his official website.

“Supreme Leader Ayatollah Ali Khamenei said Iran would need to significantly increase its uranium enrichment capacity, highlighting a gap in positions between Tehran and world powers as they hold talks aimed at clinching a nuclear accord,” Reuters reported.

Khamenei called the prospect of shutting down one key underground enrichment facility “laughable.”

Iran insists it needs to expand its capacity to refine uranium to fuel a planned network of atomic energy plants. The powers say Tehran must sharply reduce that capacity to prevent the country being able to quickly produce a nuclear bomb using uranium enriched to a far higher degree.

Atomic negotiators seemed to suggest that the announcement comes as a surprise as Iranian officials had recently reduced their amount of uranium enrichment that they sought to secure in negotiations.

Director of the non-proliferation program at the International Institute for Strategic Studies Mark Fitzpatrick told Reuters that this move confirms for him that Iranian nuclear negotiators are not free to accept terms limiting the Islamic Republic’s enrichment program.

Consenting to this latest demand is a non-starter for Western powers, and the July 20 deadline for the conclusion of talks is fast approaching.

Secretary of State John Kerry will reportedly travel to Vienna in the coming days where he will personally preside over the failure of the latest round of nuclear talks.