A U.S. official confirmed to CNN on Friday that armed drones have started flying over Baghdad in the last 24 hours to provide extra protection to the 180 U.S. military officials in the area. The U.S. had previously said the drones were unarmed.

Any drone use for offensive attacks against Iraqi insurgents would require President Barack Obama's approval.

On Friday, Kurdish leader Masoud Barzani said disputed areas of northern Iraq, including the oil-rich city of Kirkuk, are now Kurdish cities because the Iraqi central government failed to hold a referendum.

This month, the Iraqi army left Kirkuk, and the Kurdish forces took control of it and other villages in the area. ISIS has been on the offensive and has taken control of several northern Iraq cities.

With tensions rising in Iraq, the U.S. and its allies may have a difficult time convincing Iraqi leaders to form a new government that unites all three groups -- Sunnis, Shias and Kurds.

Barzani, president of the Kurdistan region, blames the Iraqi government for not holding a referendum on Kirkuk and the nearby villages.

"We have waited for more than 10 years for the Iraqi federal government to address and solve the issue of these areas covered by Article 140, but it was of no avail," Barzani said at a joint appearance with British Foreign Secretary William Hague.

The 2005 Iraqi Constitution said the final status of disputed areas -- Kirkuk and small villages in Nineveh and elsewhere -- would be determined by a referendum. That referendum never took place because of regional tensions.

American and Arab diplomats say they likely won't pursue military strikes against ISIS and its fighters until a new Iraqi government is formed. But forming that government is expected to take time.

Iraqi military commanders have said they need airstrikes to prevent ISIS advances, but Obama has only promised the help of 300 U.S. military personnel to assist Iraqi security forces. No airstrikes have been authorized.

With ISIS and Iraq in constant dispute over territories, reports have surfaced of Iraqi forces killing Sunni prisoners.