US Secretary of State John Kerry has arrived in Vienna for talks with foreign ministers about Tehran's nuclear program.
Iran and the six powers- Britain, the US, France, Germany, Russia and China- aim to reach a long-term deal to end the decade-old nuclear standoff by July 20.
A campaign for recognition and compensation for servicemen exposed to UK nuclear weapons during tests in the '50s took a step forward today.Read the full story ›
Iran's Supreme Leader described Western expectations for his country to curb its missile development as "stupid and idiotic," striking a defiant tone ahead of a fresh round of nuclear talks.
Ayatollah Ali Khamenei called on Iran's Revolutionary Guards to mass produce missiles and said the nuclear negotiations were not the place to discuss Tehran's defence programme.
"They expect us to limit our missile programme while they constantly threaten Iran with military action," Khamenei was quoted as telling the IRNA news agency.
Iran and the United States, France, Germany, Britain, China and Russia will reconvene in Vienna on Tuesday for a new round of nuclear talks.
Opposition politicians have called for a parliamentary inquiry into the handling of a radiation leak at a nuclear test reactor.
Public confidence has been damaged by the incident at the Vulcan Naval Reactor Test Establishment in Dounreay, Caithness, according to shadow defence secretary Vernon Coaker and shadow Scottish secretary Margaret Curran.
UK Defence Secretary Philip Hammond revealed details of a small internal leak of radiation on Thursday as he announced that the nuclear submarine HMS Vanguard is to have its reactor refuelled at a cost of £120 million.
Mr Coaker and Ms Curran said there were "significant questions" about the handling of the incident, particularly the two-year delay in making it public.
Russia may suspend nuclear arms inspections in a treaty with the US in reaction to Western sanctions over Ukraine, Russian news agencies quoted an unnamed defence ministry source as saying.
"The ungrounded threats to Russia from the US and NATO over its Ukrainian policy are regarded by us as an unfriendly gesture and allow us to announce force majeure," the unnamed source was quoted as saying by the state-owned RIA Novosti news agency.
"We are ready to take this step as a response to the Pentagon's statements about suspension of engagements between the armies of Russia and the US," the source added.
A spokesperson for the White House has confirmed that the US will follow through on its commitment to reduce some of the sanctions against Iran as laid out in a recent nuclear deal.
The spokesperson added that the US and its partners will "continue our aggressive enforcement" of the sanctions that remain in place.
A State Department source said that the US was "clear-eyed" about the difficulties that remain in addressing international concerns about Iran's nuclear programme.
Iran has said it will suspend its uranium enrichment in a few hours once talks with the UN nuclear watchdog have ended, the country's Fars news agency has reported, quoting an official.
The International Atomic Energy Agency and our experts are in technical talks ... after that ends, I believe the suspension will start around noon (local time).
A landmark deal curbing Tehran's nuclear programme is being implemented by world powers and Iran.
Iran will begin to freeze part of its nuclear programme in return for the sanctions relief from January 20.
The deal, agreed between Iran and world powers after months of negotiation led by the EU's foreign policy chief Catherine Ashton, is hinged on Iran curbing its enrichment of uranium.
Officials have another six months from January 20 to agree a final settlement about the activity the West suspects is aimed at obtaining nuclear weapons capability.
William Hague has hailed implementation of an interim deal to freeze Iran's nuclear programme.The Foreign Secretary said the agreement coming into force was an "important step" in settling the differences between the Middle East and international powers.
The entry into force of this agreement on January 20 is an important step towards peacefully resolving the Iranian nuclear issue, on which comprehensive negotiations will now start.
The United States said that although sanction relief will begin immediately the full benefits will not be released until the deal reaches its end.
The United States and the rest of our P5+1 partners will also take steps, in response to Iran fulfilling its commitments, to begin providing some limited and targeted relief.
The $4.2 billion in restricted Iranian assets that Iran will gain access to as part of the agreement will be released in regular installments throughout the six months.
The final installment will not be available to Iran until the very last day.