Foreign fighters and would-be suicide bombers are fleeing the Islamic State to Turkey and attempting to defect to other groups after becoming disillusioned, a Syrian watchdog organization claimed this week.

The claim was made by Raqqa is Being Slaughtered Silently (RBSS), which monitors and reports on developments in Raqqa, which the Islamic State, also referred to as ISIS, has claimed as the seat of its so-called caliphate. The group told the Independent that it sources its information from residents still living in the city.

In a statement on its website this week, RBSS described how the Islamic State has erected barriers and checkpoints to prevent fighters from leaving Raqqa and that the defections represent instabilities in the group that could lead to its downfall. The watchdog also cites the demoralizing effects of US-led airstrikes and the loss of Kobane earlier this year, writing that "fear is spreading in the ranks of the group."

Many fighters who were designated to become suicide bombers have fled to Turkey after paying large sums of money, the group claims, while others have sought refuge in territory controlled by the al Nusra Front. RBSS has not yet answered additional questions from VICE News.

"Raqqa city has experienced internal unrest… (that) may cause cleavages (that) lead to the full collapse within the group," RBSS also claimed. "Hope is returning and taking shape in the hearts of the rest of the people in Raqqa, who are waiting for the freedom sunrise again all over the captive city."

The group's claims are supported by other reports that fighters are trying to flee the Islamic State, a development that US-based experts say is not surprising and has been seen in the past with other terror groups. The sense of purpose and excitement that inspires fighters to join the cause wears thin when they are taking losses, Scott Stewart, vice president of tactical analysis at the global intelligence and advisory firm Stratfor, told VICE News.

"It would not be surprising. We have seen that in the past, even during the al Qaeda in Iraq days, where people got cold feet after being asked to do suicide bombings," Stewart said. "Certainly right now with the pressure the Islamic State is under, I can understand people wanting to give up the cause. It's one thing when you're slaughtering the Syrians, but when you start taking serious losses, like the carnage they felt in places like Kobane, the narrative is changing."

Patrick Skinner, former CIA case officer and director of special projects at the Soufan Group, told VICE News: "This is the first I've seen of people specifically referred to as would-be suicide bombers leaving. But since ISIS mostly uses foreign fighters as human missiles, it makes sense that fleeing fighters could be described as would be suicide bombers."

Many fighters traveled to Syria and Iraq "not quite knowing what they were getting into, and who are now trying to get out," Marina Ottaway, senior scholar in the Middle East Program of the Wilson Center, told VICE News. The apparent harsh reaction by Islamic State officials to the defections shows how serious a problem it poses for the group, she added. "What we know is the numbers [of those fleeing] are sufficiently high and ISIS is publicizing the punishment it metes out to people that are trying to leave to deter them. They are worried about people leaving."

An estimated 15,000 to 20,000 foreign fighters are believed to have journeyed to Syria and Iraq in 2014. Residents of Western Europe, North Africa, the Middle East, and the US have all been caught traveling or planning to travel to join the fight, and those that have joined have used social media to post about the glamorous life they've been leading. But experts say the realities under the Islamic State do not match up with the romantic idea many fighters had about it prior to arriving.

"Younger guys can be very idealistic and get sucked into these things and then get over there and find out it's not really what they thought it was going to be," Stewart said. "It's one thing to fight and achieve martyrdom there and it's another to ask someone to be a suicide bomber."

"I think it's not too difficult to figure out why they are leaving," Ottaway said. "A lot of young kids go there not quite knowing what they're getting into. They have a romantic idea they are going to fight for this great idea, the caliphate, and they get there, particularly the kids who have grown up in the Paris suburbs or communities in the US, and they are totally unprepared for the reality of war, what they are being asked to do, and what ISIS is like, and I think they become disenchanted."

More than one expert compared the situation to the Eagles' song, Hotel California, in which "you can check out but you can never leave." Fighters who escape to Turkey and then try to re-enter other European countries will likely be flagged and stopped from doing so because of their involvement with the Islamic State, Stewart said.

"Hiding from air strikes is far removed from the video game excitement that ISIS promised," Skinner said. "There will be many more who come to regret their decision, and ISIS will push hard to stem the tide before it becomes a flood." He added dryly that the development represented "the management downside of running an organization staffed with psychopaths and suicidal recruits."

RBSS and the experts VICE News interviewed couldn't put a precise number on how many fighters were trying to leave or had successfully left, but all said that the significance is in the fact that they are trying do so after wanting to fight. The development suggests cracks in the unity of the Islamic State and points to a slowing momentum. Stewart also pointed to the airstrikes, the loss of Kobane and the Sinjar area, and the start of forced conscription of members in parts of Syria as signs that the group is struggling. "It's an indication they're hurting for bodies," he said.

"It's too early to say they're falling apart," Ottaway emphasized, however. "The organization has suffered some defeats and probably lost some of the luster from when they first took over Mosul and had an aura of invincibility around it…. Now it is clear they have strengths and weaknesses."