Iran vows 'irreversible steps' on nuclear programme

Iran will resume talks with world powers on a final nuclear agreement on April 21 and is ready to take "irreversible steps" if the West does the same, Iranian Foreign Minister Mohammad Javad Zarif said Tuesday in Spain.

"My team, the assistant to (EU foreign policy chief Federica) Mogherini and the other representatives of the 5+1 (global powers) will meet next Tuesday to begin drafting the text," he told a conference in Madrid.

He did not say where the talks would take place but later gave more details about his country's position.

"This is the framework under which we will operate with the 5+1 group: (there will be) irreversible steps on the Iranian side as long as their side takes irreversible steps. It is a very balanced approach," said Zarif, Iran's chief nuclear negotiator.

He was referring to the so-called P5+1 powers -- Britain, China, France, Russia, the United States and Germany -- who have been negotiating with Iran to end the 12-year standoff over its nuclear programme.

The six countries made a major breakthrough at talks with Iran on April 2 by agreeing on the parameters for a final deal to scale back its nuclear capabilities.

But the negotiators still have a series of technical issues to resolve by a June 30 deadline for a final deal, including the steps for lifting sanctions imposed on Iran.

"Iran will take all the measures that are required in the initial phase, all the measures," Zarif added during a joint news conference with his Spanish counterpart Jose Manuel Garcia-Margallo.

"If we are going to reduce the number of centrifuges we will do that in the first days, we are also called to redesign the Arak reactors into another hardwater reactor, we will do that in the initial steps," he added.

Western powers want Iran to re-design a planned research reactor at Arak to cut its potential output of plutonium, one of the materials needed to produce a nuclear bomb.

Oil-rich Iran denies Western claims that it is seeking to make a nuclear bomb.

- 'Congress is their problem' -

Iran's Supreme leader Ayatollah Ali Khamenei, who will have the final say on any deal, has cast doubt over the accord, saying that "nothing is binding".

President Hassan Rouhani has demanded that sanctions be lifted as soon as any deal is signed.

Zarif said that all the elements "required for the lifting of sanctions will take place in the first phase."

The P5+1 have said sanctions will only be gradually eased and want a mechanism to ensure they can be swiftly reimposed if Iran breaks its word.

US Secretary of State John Kerry has come under fire at home for pushing the deal, with many US lawmakers still wary of Iran, a long-time US foe, which has not had full diplomatic relations with Washington for 35 years.

Republican Senator Bob Corker, who has co-sponsored a bill that would give Congress the power to review any final deal, said Monday he might be garnering enough support to overcome any veto by President Barack Obama.

Zarif said he expected Washington to lift the sanctions.

"On the American side, we behold the government of the United States to be responsable," he said, adding that obtaining approval from Congress was "their problem".

"As far as we are concerned, they have to terminate the implementation of those sanctions and that is their legal obligation," he said.

Spain currently chairs the United Nations Sanctions Committee.

"We will try to reach a consensus so the sanctions disappear as Iran adopts the measures it has committed itself to do," said Garcia-Margallo.