U.S. and Iraqi officials said they are looking for a group of Americans reported missing in Iraq. At least three individuals were reported missing Sunday in Baghdad, media reports said.

"We are aware of reports that American citizens are missing in Iraq," State Department spokesman John Kirby told Agence France-Presse. "The safety and security of American citizens overseas is our highest priority.‎"

Kirby did not identify the missing persons. He said the U.S. government is "working with the full cooperation of the Iraqi authorities to locate and recover the individuals."

A senior Iraqi security official said a company filed a report Sunday that three of its American contractors went missing two days ago. "We are looking into this report," the official told CNN.

The U.S. Embassy in Baghdad separately confirmed "several" Americans are missing in Iraq, the Associated Press reported. His comments came after the Arab news channel, al-Arabiya, reported three Americans were kidnapped by militias in Baghdad.

The incident follows a week of escalating tensions and deteriorating security in and around the Iraqi capital. The Islamic State group killed more than 50 people in a series of attacks in Baghdad and Diyala province last week, including an assault on a popular mall in Baghdad, the AP said.

News of the missing Americans came the day after Iran released multiple American detainees as part of a prisoner swap.

Saeed Abedini, an Iranian-American Christian cleric, the Washington Post's Tehran bureau chief Jason Rezaian and Amir Hekmati, a former Marine from Flint, Michigan, boarded a plane from Tehran Sunday. The group has since arrived in Germany following a stopover in Geneva.

Nosratollah Khosravi-Roodsari also was released as part of the exchange for seven Iranians being held by the U.S. but did not board the plane. Student Matthew Trevithick was separately freed this weekend and also reportedly stayed behind. The fates of three other Americans being detained in Iran, including former FBI agent Robert Levinson, were still unknown Sunday.