French police suspect that people who put pigs' heads outside Paris mosques on Monday night were acting under orders from a foreign intelligence service, probably Russian.

The heads were found on Tuesday morning outside nine mosques in central Paris and surrounding suburbs, prompting a wave of outrage and condemnation.

But investigators have now said the two people involved drove a Serb-registered car, used a Croatian mobile telephone, and crossed into Belgium a few hours later.

The incident has striking similarities with other recent provocations – notably the daubing of Stars of David on Paris walls in October 2023, and the painting of red hands on the city's Holocaust memorial in May 2024.

Police identified a Moldovan connection in the first case, and in the second four Bulgarians are due to stand trial in October.

The prosecutor in the red hands affair said it appeared 'to be an attempt to destabilise France orchestrated by Russian intelligence'.

Russia and Iran have both been named by French intelligence as countries liable to provoke dissension in France through 'dirty tricks'.

Police investigating the latest affair told media that they were approached by a Normandy farmer who said he had sold about 10 pigs' heads to two men driving a Serbian-registered car.

The same car was seen in CCTV footage in the Oberkampf region of eastern Paris on Monday evening, and then again near some of the mosques.

Police said tracing of the Croatian mobile phone showed the car crossing into Belgium early on Tuesday morning.

Video footage obtained by news channel BFMTV shows a man in a white T-shirt, cap and surgical mask placing a pig's head outside a mosque in the south-western suburb of Malakoff. He is seen taking a photograph before leaving, carrying a rucksack.

At roughly the same time, another person is seen doing the same at a mosque in the eastern suburb of Montreuil.

In the Stars of David affair, the perpetrators were also seen taking photographs of their work – an act interpreted as a way of proving they had done what they were paid to do, but also to form the basis of a subsequent social media campaign.

The same patterns of provocations have emerged in past incidents, suggesting a larger pattern of interference aimed at inciting conflict within France. French police are enhancing their efforts to combat such activities and maintain social cohesion.