Iran said on Monday there would be no new nuclear talks with the United States if they were conditioned on Tehran abandoning its uranium enrichment activities.

Iran's nuclear program may get more difficult to monitor if no deal is reached with the United States. The U.N. nuclear watchdog has withdrawn its inspectors and nuclear experts believe Iran relocated more than 400 kilograms of highly enriched uranium—enough for 10 nuclear weapons—to a secret location.

A senior Israeli official says Israel believes deeply buried stocks of enriched uranium at one Iranian nuclear facility hit by the U.S. military are potentially retrievable.