The European Union has said that world powers have agreed to a new round of talks with Iran over its nuclear programme, as Tehran gave permission for inspectors to visit a site suspected of secret atomic work.
The two developments appeared to counter the crisis atmosphere over Iran's nuclear development programme, the focus of talks in Washington between President Barack Obama and Israel's visiting prime minister.
EU foreign policy chief Catherine Ashton said the five permanent members of the UN Security Council - the US, the UK, China, Russia and France - and Germany agreed to a new round of nuclear talks with Iran.
Previous talks have not achieved what the powers want, an end to uranium enrichment on Iranian soil. The last round of negotiations in January 2011 ended in failure.
The US and its allies believe Iran is trying to build nuclear weapons. Tehran denies that, insisting that its programme is for peaceful purposes.
Baroness Ashton said in a statement that the EU hopes Iran "will now enter into a sustained process of constructive dialogue which will deliver real progress in resolving the international community's long-standing concerns on its nuclear programme". The time and venue of the new talks have not been set.
Foreign Secretary William Hague said the onus would "be on Iran to convince the international community that its nuclear programme is exclusively peaceful".
German foreign minister Guido Westerwelle called for a diplomatic solution, adding: "A nuclear-armed Iran must be prevented."
The UN's International Atomic Energy Agency (IAEA) last year published a report that included what it said was evidence of Iranian activity that could be linked to weapons development. The head of the IAEA, Yukiya Amano, said on Monday that his organisation had "serious concerns" that Iran might be hiding secret atomic weapons work, singling out the Parchin military complex south-east of Tehran.
Iran appeared to respond partially to those concerns, granting long-sought permission to IAEA inspectors to visit the Parchin compound. Iran describes the site as a military base, not a nuclear facility.