ALMATY, Kazakhstan – World powers, fearful of scuttling negotiations beginning this week with Iran, are offering the Islamic republic some small new sanctions relief in return for curbing its nuclear program. But officials warned Monday that it's unlikely that any compromise will be reached soon.

Negotiators set low expectations for the latest round of high-level diplomatic talks to begin Tuesday in Kazakhstan's largest city – the first since last June's meeting in Moscow that threatened to derail delicate efforts to convince Iran to stop enriching uranium to a level close to that used for nuclear warheads.

The stakes couldn't be higher: the Obama administration is pushing for diplomacy to solve the impasse but has not ruled out the possibility of military intervention in Iran to prevent it from acquiring a nuclear weapon. And Israel has threatened it will use all means to stop Iran from being able to building a bomb, potentially as soon as this summer, raising the specter of a possible Mideast war.