Iran’s Arak nuclear facility. Photo: Nanking2012 via Wikimedia Commons.

The United States on Friday granted waivers allowing Britain, China, France and Russia to continue nonproliferation work with Iran, permitting them to maintain projects designed to make it harder for Tehran to build an atomic weapon, Assistant Secretary of State Christopher Ford told Bloomberg.

Instead of granting the waivers for 180 days, the administration will shorten their term to 90 days, Bloomberg said.

Under the 2015 nuclear deal with six major powers, Iran agreed to transform its nuclear facilities at Arak and Fordow in ways that would make it much more difficult to use them to produce fissile material for nuclear weapons.