Deputy U.S. Secretary of State Bill Burns has met with Iranian officials for a short time on Monday on the sidelines of the broader talks between Iran and six world powers in Vienna on Tehran's nuclear program, but Tehran has denied that .

The spokeswoman for the U.S. State Jane Sacchi told reporters "We are ready for the continuation of our engagement with the Iranians, just as we communicate with other players in the region on the threat posed by the Islamic State in Iraq and the Levant organization on Iraq."

"It is likely ... that these discussions would take place at a lower level. Do not expect further dialogues with Iran on this issue in Vienna. These talks will focus on the nuclear issue for the rest of the week."

  Islamic State in Iraq and the Levant organization has dominated large parts of the north of the country in the past week, threatening to cut Iraq apart and outbreak of sectarian war.