By Yeganeh Torbati and Justyna Pawlak
ALMATY | Tue Feb 26, 2013 3:55pm EST
(Reuters) - Major powers offered Iran limited sanctions relief in return for a halt to the most controversial part of its atomic work during the first day of nuclear talks on Tuesday, and Iran promised to respond with a proposal on the same scale.
The talks in Kazakhstan were the first in eight months between Iran and the five permanent members of the U.N. Security Council plus Germany - the "P5+1" - on a decade-old dispute that threatens to trigger another war in the Middle East.
Iran has used the time since the last meeting in June to further expand activity that the West suspects is aimed at enabling it to build a nuclear bomb, something that Israel has suggested it will prevent by force if diplomacy fails.
Western diplomats described the first day of talks as "useful" but said Iranian negotiators did not immediately respond to the P5+1's demand that Tehran closes its underground nuclear facility Fordow, at the center of their concerns.