By Matt Spetalnick

WASHINGTON (Reuters) - Getting Iran to suspend higher-level uranium enrichment and close a nuclear facility built deep under a mountain are "near-term priorities" for the United States and its allies, a senior U.S. official said on Sunday as new talks loomed over Iran's nuclear standoff with the West.

Iranian media said negotiations between Tehran and world powers would take place on Friday in Istanbul, resuming talks that collapsed more than a year ago. Although Washington had expressed a preference for Istanbul, there was no immediate confirmation of the venue from Western capitals.

Ahead of the much-anticipated meeting, efforts were under way to define the parameters for negotiations that the Obama administration has said could represent Tehran's last chance to resolve the nuclear dispute diplomatically.

The New York Times cited U.S. said European diplomats saying the United States and other Western nations planned to demand that Iran immediately close and ultimately dismantle its recently completed Fordow facility near the Shi'ite Muslim holy city of Qom. It said they also would call for a halt in the production of 20 percent enriched uranium.

A senior U.S. official told Reuters "20 percent and closing Fordow are near-term priorities" for the Obama administration and its international partners in dealing with Iran.

Iran has remained defiant, saying its program is for power generation and producing isotopes for medical purposes, not for bomb-making.

But the U.N. Security Council has demanded a full suspension of enrichment, both to the 20 percent and the 3.5 percent level, and Washington has made clear that its broader goal is to make sure that Iran abides by those requirements.

President Barack Obama is under pressure at home to take a tough line with Iran as he seeks re-election in November. Republican presidential candidates have accused him of not being hard enough on Iran, even as he has spearheaded international sanctions that are taking toll on the Iranian economy and its vital oil sector.

He has pressed U.S. ally Israel to hold off on any pre-emptive military strikes on Iran's nuclear sites to give sanctions and diplomacy more time to work. But he has also declared that military action remains an option as a last resort.

(Reporting By Matt Spetalnick; Editing by Bill Trott)