The International Atomic Energy Agency (IAEA) on Sunday welcomed the agreement reached between P5+1 and Iran, calling it "another important step forward".

The agreement between the P5+1 group, the five UN Security Council permanent members Britain, China, France, Russia and the United States plus Germany, and Iran on a joint action plan to be implemented over the next six months is another important step forward following the agreement reached between the Agency and Iran on Nov. 11 in Tehran, said IAEA Director General Yukiya Amano in a statement.

"The Agency will be ready to fulfil its role in verifying the implementation of nuclear related measures," said Amano.

After days of intensive negotiations, the P5+1 group and Iran reached a first-step agreement on Iran's nuclear program on Sunday morning.

According to the White House, in the agreement Iran has been committed to halting enrichment above 5 percent and neutralizing its stockpile of near-20 percent uranium by means of dilution or converting.

Furthermore, Iran has been committed not to installing more centrifuges, halting work at its plutonium reactor at Arak, and allowing IAEA inspectors' daily access to its enrichment facilities at Natanz and Fordow, the White House said.

On Nov. 11, Iran and IAEA also signed a cooperation deal to enable the UN nuclear watchdog to have access to more Iranian nuclear facilities for inspection.

The western states have long suspected Iran is developing its nuclear weapon program under the cover of a civilian atomic plan, which Tehran denies, saying it's solely peaceful.