(Reuters) - Senior U.N. inspectors arrived in Iran on Monday to push for transparency about its disputed nuclear program and several European states halted purchases of Iranian oil as part of Western moves to pile pressure on a defiant Tehran. 

Iran denies Western accusations that it is covertly seeking the means to build nuclear weapons and has again vowed no nuclear retreat in recent weeks, but also voiced willingness to resume negotiations with world powers without preconditions.

 

The five-member International Atomic Energy Agency team, led by chief IAEA inspector Herman Nackaerts, planned two days of meetings in another attempt to get answers from Iran regarding intelligence suggesting its declared civilian nuclear energy program is a facade for researching ways to make atom bombs.