Their encirclement by the Syrian Army in the final battles along the Syrian-Iraqi border, have left them only the remote desert areas elsewhere or escaping to Turkey, according to local commanders and intelligence officers.
Many foreign fighters are thought to have been killed on the battlefield, and some 6 000 have returned home, according to data from 33 countries of origin.
But even the most liberal estimate of those killed, still leaves thousands of foreign fighters at large.
“We are encountering foreign fighters here every day,” Abu Ibrahim, a local Syrian Democratic Forces (SDF) commander, told The Times. He leads a force of 1 500 Arab fighters.
Syria’s SANA news agency has reported, citing eyewitnesses, that this week US helicopters evacuated ISIS leaders from several areas across the Syrian province of Deir Ezzor to to safety in al-Hasakah province.
Most of the area is presently under the control of Kurdish and US forces.
Russian General Staff Chief Valery Gerasimov this week said US instructors were training ISIS militants at two military bases, where US special forces operate.
“There was a threat of seizure of the city Al Quaryatayn in Syria. Their forces were defeated. It is clear that the militants are being trained there,” Gerasimov said.
Responding to findings of a recent study on what motivates both ISIS fighters, Arie W. Kruglanski, distinguished professor of psychology at the University of Maryland and former co-director of the US National Consortium for the Study of Terrorism and Responses to Terrorism, noted that: “The ideology component addresses individuals’ need to matter and feel significant. … It tells people what to do, such as fight and make sacrifices, in order to gain respect and admiration from others.”
Kruglanski added: “Especially when it comes to violence that is shunned by most religions and most cultures, you need validation from a group of people that would then become your reference group. So the group component is very important, particularly when it comes to antisocial activities that are forbidden or shunned.”
German domestic intelligence meanwhile, has warned of a growing number of Islamic extremist women radicalising a next generation of young jihadis.
The Agency for the Protection of the Constitution in North Rhine-Westphalia believes that the Islamic extremist scene is becoming increasingly more influenced by women.
Burkhard Freier, head of the regional branch of the agency, told German daily Die Welt that at least 40 female radicals were currently under observation.
“The men have come to realise that women do networking much better and as such are much more able to keep the group together and dynamic,” Freier noted.
“This makes Salafism a family affair, it begins to create something that is much harder to liquidate, namely a Salafist society,” Freier said, adding that “every jihadist terrorist we’ve seen in Europe in recent years came from the Salafist scene.”
“There is an increasing number of underage Salafists who fantasise about violence,” he said.
Ali Soufan, a former FBI officer who heads the Soufan Group, a risk consultancy firm in New York said: “People who want to continue to be on the path of ISIS and on the jihad of ISIS will have ample opportunity to do so, whether in their own home countries or in third countries or in other conflict zones where ISIS is operating.”
Guy Mettan, a Swiss politician, president of the Swiss Press Club and author told Radio Sputnik that the US would continue to support ISIS.
“In Syria, the liberation came from Russia, and from the government troops with the support of Iran. And now it’s very difficult for such a power as the United States to recognise its failure.
“That is the reason why, I think, they are trying again and again to give support to jihadists,” Mettan said.