Developments in Iran Nuclear Standoff:
2013
January: Iran says it will speed up nuclear fuel work.
February: Iran's supreme leader Ayatollah Ali Khamenei rejects direct nuclear talks with the US.
2012
January: IAEA confirms Iran is refining uranium to 20% fissile purity.
February: UN inspectors end talks in Tehran without inspecting disputed military site at Parchin.
April: Iranian President Mahmoud Ahmadinejad vows Iran will not surrender its nuclear rights.
May: UN inspectors report they found find traces significantly upgraded uranium at an Iranian site.
July: EU begins total ban on Iranian oil imports, US expands sanctions.
September: IAEA demands access to Parchin, Iran calls EU sanctions "irresponsible."
December: IAEA says it makes progress in talks with Iran. US imposes more sanctions.