Arak heavy water production facility in Arak, Iran (file photo)

Iran and the U.N. International Atomic Energy Agency (IAEA) say they have agreed on a timetable for Tehran to clear up outstanding questions about its controversial nuclear program.

IAEA Deputy Director Olli Heinonen and Iranian nuclear negotiator Javad Vaeedi announced the agreement Tuesday after two days of talks in Tehran.

Vaeedi said the talks produced great results.

Neither side gave details on the timetable agreed to in the talks, which came ahead of an IAEA report on Iran that is due for release next month.

Earlier Tuesday, a top U.S. diplomat said Iran's efforts to continue discussions with the IAEA will not stop Washington from pushing for tougher U.N. sanctions against Iran.

U.S. Under Secretary of State Nicholas Burns said Iran should have answered the United Nations' questions about its nuclear program years ago.

The U.N. Security Council has imposed two sets of sanctions on Iran for its refusal to suspend uranium enrichment, a process that can be used to make nuclear weapons.

The United States and its allies accuse Iran of seeking to build atomic weapons under the cover of a civilian program to generate electric power.  Iran denies the charge.

Some information for this report was provided by AFP, AP and Reuters.