Biden says Obama "not bluffing" on Iran nuclear threat (2)

Iranian chief nuclear negotiator Saeed Jalili expressed optimism Wednesday about the outcome of the nuclear talks, saying that the attitude of the world powers toward Iran's nuclear issue was "more realistic".

The U.S. government welcomed Iran's interest in the proposal presented by world powers at the talks in Kazakhstan. However, Washington insisted that Tehran take "concrete steps" to address international concerns and comply with its international obligations regarding its nuclear program.

Iran and the world powers agreed to hold an expert-level meeting in Istanbul, Turkey on March 17 and 18, and another high- ranking meeting in Almaty, Kazakhstan on April 5 and 6.