Senior U.N. investigators have opened a new round of talks with Iranian officials in the hopes of restarting a probe into Iran's suspected work on nuclear arms.

Iran's semiofficial ISNA news agency says the negotiations began at the Atomic Energy Organization of Iran headquarters in Tehran Wednesday morning. It didn't provide any further details.

Before departing Tuesday for Iran, U.N. team leader Herman Nackaerts said the International Atomic Energy Agency hoped to "finalize the structured approach" that would outline what the agency can and cannot do in its investigation.

The U.N. nuclear watchdog agency has tried for more than a year to restart its stalled investigations into allegations that Iran has worked on developing atomic weapons. Tehran steadfastly denies any such activity.