four days of talks between Iran and the P5+1
The four days of talks between Iran and the P5+1 - the US, UK, France, China and Russia plus Germany - will begin with a working dinner at Vienna's Palais Coburg hotel for Iranian Foreign Minister Mohammad Javad Zarif and EU foreign policy chief Catherine Ashton.
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Iran nuclear deal
20 January - First day of implementation of interim nuclear deal. IAEA begins verifying Iranian compliance; P5+1 and EU suspend sanctions
18 February - Iran and P5+1 begin talks in Vienna to find a "comprehensive solution"
19 July - Expiry of six-month interim period for finding comprehensive solution. If not renewed by mutual consent, P5+1 may increase sanctions
November - Iran and P5+1 aim to "conclude negotiating and commence implementing" the second step of any comprehensive solution
Iran nuclear deal: Key points
Diplomats say there is political will on both sides to reach an agreement, but that it will be very difficult to overcome differences on three key issues:
Iran's uranium enrichment capacity
The heavy-water reactor at Arak
And the possible military dimensions of Iran's nuclear programme.
On Monday, Iranian representatives attended a meeting at the headquarters of the International Atomic Energy Agency (IAEA) in Vienna.
The global watchdog was said to have sought clarification about Tehran's efforts to develop exploding bridge wire (EBW) detonators, which could be used in nuclear weapons.
Iran has agreed to provide such information by Thursday, as part of a series of steps to allay the P5+1's concerns about its nuclear activities. Other steps include allowing IAEA inspectors to visit the Saghand uranium mine and the yellowcake production plant at Ardakan, which happened last week.
On Sunday, President Hassan Rouhani warned that Iran would not surrender its "right" to nuclear development at the Vienna talks.
"If the world seeks good relations with Iran, it should choose the way of surrendering to Iran's rights, respecting the Iranian nation and praising Iranian scientists," he told a group of medical and nuclear experts Monica Lewinsky first grabbed headlines ���Ĺª��غ�һ���� �t�y�z���V��֪ �����ڱ�����չ����� perfection consider myself driving style ���Թ���H�ǂ����Y �к����H��ԇ������ͨ ����Ҹ��H�K��ܛ�� ���I���x�e����лؑ� ������·�fǧ�l.