French police have arrested a 22-year-old man suspected of planning an attack on American and Russian tourists, a legal source has said.
The suspect had gone to Carcassone, southern France "with a view to carrying out a violent act, in particular targeting Americans and Russians," a judicial source told AFP on Thursday.
A source close to the investigation said the suspect was arrested in possession of a knife and a small mallet.
The arrest comes after an extremist claiming allegiance to Isis stabbed a police officer and his wife to death in a Paris suburb.
Larossi Abballa, 25, killed Jean-Baptiste Salvaing and his wife at their home. Police said Abballa had lain in wait outside the house in Magnanville, a commune northwest of Paris, and stabbed Mr Salvaing as he arrived home at around 8.30pm local time (7.30pm BST) then going inside to murder his wife on Monday.
He then held their three-year-old son hostage for several hours before being shot dead by officers during a standoff with armed police.
Speaking in a video filmed as he held the boy hostage, Abballa pledged allegiance to Isis and said he was obeying a call to carry out lone wolf attacks during Ramadan. He also claimed the Euro 2016 football tournament being held in France would be turned into "a graveyard".
France has been on high alert as it hosts the Euro 2016 football tournament, where violence has been seen between fans, and is still under a state of emergency following Isis’ Paris attacks in November.
The threat “is high in France, it's high in Europe, it's high in the Western world, as shown by the events that happened 48 hours ago in the United States,” Mr Interior Minister Bernard Cazeneuve said.
