French and Algerian fighters, some arriving from Syria, have joined the ranks of the Islamic State group in northern Afghanistan where the militants have established new bases, multiple international and Afghan sources have said.
It is the first time that the presence of French IS fighters has been recorded in Afghanistan, and comes as analysts suggested foreigners may be heading for the war-torn country after being driven from Syria and Iraq.
It is also a troubling sign as France, which has faced the worst of the IS-inspired violence in Europe since 2015, debates how to handle hundreds of its citizens who went to fight for the group in the Middle East.
"A number" of Algerian and French nationals entered the largely IS-controlled district of Darzab in northern Jowzjan province in November, said district governor Baaz Mohammad Dawar.
At least two women were among the arrivals, who were travelling with a translator from Tajikistan as well as Chechens and Uzbeks, Dawar added.
European and Afghan security sources in Kabul confirmed Dawar's claim that French citizens were among the fighters -- though, one cautioned, "we do not know how many there are".
Three of the Algerians seen in Darzab are believed to have been in Syria and Iraq, Dawar said, suggesting they may link Islamic State-Khorasan Province (IS-K), the group's franchise in Afghanistan and Pakistan, with the main group in the Middle East.
When it first emerged in 2015, IS-K overran large parts of eastern Nangarhar and Kunar provinces, though initially its part in the Afghan conflict was overshadowed by the Taliban.
The jihadists have since spread north, including in Jowzjan on the border with Uzbekistan, and carried out multiple devastating attacks in the capital Kabul.
Mohammad Raza Ghafoori, the Jowzjan provincial governor's spokesman, said French-speaking Caucasian men and women had been seen training IS fighters in Darzab.
He cited reports saying that around 50 children, some as young as 10, have also been recruited by the fighters.
Darzab residents told AFP that roughly 200 foreigners had set up camp just a few hundred metres (yards) from the village of Bibi Mariam.
One local man who gave his name as Hajji said the fighters were of several nationalities, including French, and were tall, aged in their late 20s, and dressed in military clothing.
"They ride their (motor) bikes, go to the border and come back, but they talk to nobody," he said.
Hashar, a former district village chief, said some were training others to use suicide bombs and lay mines.
"They are... bringing misery to normal people," he told AFP, as other villagers said many residents had fled the area.
Locals along with district governor Dawar warned the fighters were also exploiting natural resources, such as precious stones and metals.
One of the security sources said that two of the French had been nicknamed "The Engineers" and appeared to be organising some sort of extraction, "but we do not know what they are looking for".