(Newsmax) Former Guantanamo Bay detainees may have joined up with the Islamic State or other extremist groups within the Syrian border, according to senior Defense Department and intelligence officials.

It’s not known just how many released detainees have joined ranks with the Islamic State (ISIS), al-Qaida, or its affiliated al-Nusra Front in Syria, but sources told Fox News that at least 20 to 30 may be involved.

Other former detainees are helping the groups from outside through financing operations and support for their propaganda campaigns, the sources said.

Much of the ISIS propaganda to date includes the heavy use of social media to actively recruit new fighters and spread the militants’ jihadist message to people around the world.

It appears, though, that only a few dozen of those being released from Guantanamo return to active fighting. According to Defense and intelligence officials, out of the 620 detainees who have been released, 180 have returned to fight with militant forces. Of those 180 people, just 20 or 30 have joined with ISIS or other militants in Syria, or are participating from outside countries. Most of the 20 to 30 people involved are inside Syria, officials told Fox.

The news that some of the prisoners leaving Guantanamo are joining militant forces may complicate President Barack Obama’s inaugural promise in 2009 to shut down the facility, which was opened in the wake of the 9-11 attacks.

But there have since then been problems with relocating prisoners, as well as the growing concerns about some returning to the battlefield. In addition, Congress has resisted allowing the detainees to be moved to American prisons.

Most jihadists who decide to return to the Middle East stay in their own countries, but the ones showing up in Syria are migrating from six European and several African countries, such as such as Egypt and Tunisia, who took them in when they left Cuba, Fox reports.

Just 149 detainees remain incarcerated at Guantanamo Bay. Ninety of them are from Yemen.

A senior administration official said earlier this month that Obama is considering the use of executive power to override a congressional ban on bringing Guantanamo Bay detainees to the United States, which would allow him to achieve his goal of closing the detention facility.

The official, speaking under conditions of anonymity to The Wall Street Journal

earlier this month, said the president is “unwavering in his commitment” to closing Guantanamo before he leaves office in two years, and considers the closure part of his presidential legacy.

We deliver meaningful conservative American news that is not your normal agenda based Beltway bull.