“I am pleased to report that we have seen important indications of significant progress towards Iran completing its key nuclear commitments under the deal,” the US secretary of state, John Kerry, said, according to The Guardian.

Under the deal between Iran and the P5+1 group of world powers, Tehran agreed to scale back its nuclear program so that Washington and its allies were assured it would no longer be on the threshold of being able to produce an atomic weapon. In return, Tehran will have access to about $100 billion of previously frozen assets and fully return to the oil market.

Read alsoSupplies of S-300s to Iran to begin in Jan 2016 – mediaLow-enriched uranium is suited to power generation but can be further enriched to yield fissile material for nuclear warheads.

Welcoming Monday’s shipment, Kerry said that by divesting itself of this low-enriched material, Iran had already trebled the amount of time it would take to produce enough fuel for a bomb from two or three months up to nine.

“The shipment included the removal of all of Iran’s nuclear material enriched to 20% that was not already in the form of fabricated fuel plates for the Tehran Research Reactor,” he said.

Read alsoUN: Iran did research and development work on nuclear armsThe International Atomic Energy Agency, the UN nuclear watchdog, will decide when Tehran has complied with its obligations, after which the US, Russia, China, Britain, France and Germany will remove some economic sanctions that targeted the program.

Tehran recently test-fired two ballistic missiles capable of carrying a nuclear warhead in breach of a UN security council resolution, in what some analysts say is part of a backlash aimed at showing a domestic audience that it has not caved in to the US.