The FBI on Thursday warned news organizations that it had recently obtained “credible information” indicating that members of an Islamic State-affiliated group have been “tasked with kidnapping journalists” in the region and taking them to Syria.

The bureau noted that supporters of the terrorist group have called on members to retaliate against the United States and its allies for airstrikes in Iraq and Syria and have identified journalists as “desirable targets.”

The warning was released as a rare intelligence bulletin to news outlets so they could take security precautions.

The Islamic State has beheaded two American journalists, James Foley and Steven Sotloff, and two British aid workers. The group is believed to be holding a number of other Western hostages.

The FBI bulletin said members of the affiliate tasked with kidnapping journalists may try to mask their affiliation with the Islamic State to gain access to journalists. The bulletin also cited a Sept. 16 online posting by an Islamic State supporter who described “media personnel, including anchormen, field reporters and talk show hosts” as being among “prioritized targets.”

The threat from the Islamic State increases the danger in reporting on what is already a difficult civil war to cover.

The U.S.-based Committee to Protect Journalists says more than 70 journalists have been killed covering the Syrian conflict since it began in March 2011.

The organization estimates 20 local and international journalists are missing in Syria. Among them is Austin Tice, a freelance journalist for The Washington Post and McClatchy Newspapers who has been missing since August 2012.

Many U.S. news organizations are no longer sending journalists to Syria but rather filing reports from Turkey and Lebanon — calling sources inside the country, interviewing refugees and aid workers, and monitoring social media.