REUTERS

The report concerns Unit 29155 of the Main Directorate of the General Staff of the Russian Armed Forces, commonly known as GRU, according to IntelNews.org, a specialist website edited by experts, which provides news and analysis on espionage, intelligence and security issues.

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"On Wednesday [December 4], a new report in the French newspaper Le Monde claimed that Unit 29155 used the French Alps as a 'rear base' to carry out operations throughout Europe," IntelNews.org said.

"Members of the unit frequently travel to Europe to carry out sabotage and disinformation campaigns, kill targets, or conduct other forms of what some experts describe as the Kremlin's hybrid war," it said.

The unit is believed to be responsible for the attempt on the life of Sergei Skripal, a former GRU intelligence officer who defected to Britain.

It is noted the alleged Russian spies stayed in France's Haute-Savoie, which borders Switzerland, and is among Europe's most popular wintertime tourist destinations. The area includes the world-famous Mont Blanc mountain range and the picturesque alpine towns of Annemasse, Evian, and Chamonix. However, the unit also utilized several other areas in Eastern Europe as rear bases, including cities and towns in Moldova, Montenegro, and Bulgaria.