The U.S. State Department is investigating reports by Middle Eastern media that American citizens are missing in Iraq, officials said Sunday.

Al Arabiya, a Saudi-owned Arab news outlet, reported Sunday that three Americans have been kidnapped by “militias” in Baghdad, citing its own sources.

State Department spokesman John Kirby said that the agency is aware of the reports.

“The safety and security of American citizens overseas is our highest priority,” Kirby said in a statement.‎ “We are working with the full cooperation of the Iraqi authorities to locate and recover the individuals.”

The State Department would not say how many Americans are reported missing. The U.S. Embassy in Baghdad told the Associated Press that “several” Americans were kidnapped.

The Americans, all contractors, went missing two days ago, reported CNN, citing a senior security official in Baghdad. Their disappearance was reported by the company where they worked, CNN wrote.

The kidnapping report comes amid a worsening security situation in Baghdad and the surrounding area, and nearly one week after armed attackers stormed a mall in the Iraqi capital and detonated suicide and car bombs, killing at least 18 people and injuring 50 more. Following the assault, which lasted about an hour and a half, authorities shut down the city’s Green Zone, a heavily guarded area that is home to several foreign embassies, including that of the United States, and Western private military contractors.

This is a developing story and we’ll update as we learn more.