Facebook groups set up to rally support for international brigades to defend Ukraine are being monitored by security agencies amid concerns that extremists could exploit the crisis, according to French media reports.
Radio station Europe 1 said about 50 people had been identified of potential concern in France including a small number holding extreme right-wing views – some backing President Vladimir Putin and others the neo-Nazi Azov Battalion, a volunteer militia that fought pro-Russian separatists in eastern Ukraine in 2014.
British anti-fascist organisation Hope not Hate said it had monitored chat groups linked to an Azov support group in which a few extremists had discussed travelling to Ukraine to join the volunteers to fight.
The crisis in Ukraine is proving a “particularly evocative and complex topic for the far right, and may well prompt further quarrels and even splits in the coming weeks and months”, the group said.
President Vladimir Putin cited groups such as the Azov Battalion, which was incorporated into the National Guard of Ukraine, as part of his reason for his “special military operation” to “de-Nazify Ukraine”.
Ukraine President Volodymyr Zelenskyy, who is Jewish, urged foreigners on Sunday to head to embassies in their countries to sign up for an international brigade to defend the country.
A private Facebook group of French volunteers for Ukraine has gathered more than 7,300 members since it was created a week ago.
It warns members to be discreet to avoid pro-Russian sabotage and cautions that going to war is not like the Call of Duty computer games.
Western governments have been divided about the legality of citizens travelling to fight in Ukraine. People cannot be stopped from travelling from France but could be prosecuted if they come back.
The military authorities stopped 14 Ukrainian members of the French foreign legion on a coach travelling to Poland, which shares a border with Ukraine.
Nine of the 14 were on leave but not authorised to travel abroad when they were stopped, while the others were considered missing or absent without leave, Legion commander Alain Lardet told AFP.
It was not known whether the 14 were planning to join the fighting in Ukraine, or simply help their families who had fled their homeland, the military command said. No weapons or other unauthorised equipment was found on them.
But some civilian passengers on the bus were carrying gear that led the authorities to believe that they planned to join the fighting.
The Foreign Legion, an elite corps comprising about 9,500 soldiers, is the only French army unit in which foreign citizens can enlist.
It has 710 soldiers of Ukrainian origin and 450 Russian-born troops, and has reported 25 desertions by Ukrainian-born soldiers, with about a dozen thought to be planning to join the fight against Russia.
The commander said the legion had “cut them loose” and that: “They are fighting for a cause that it is not my role to judge.”