A man armed with two loaded pump-action shotguns and a knife has been arrested in the French city of Cannes, local media have reported.

The country is on high alert after a series of incidents in recent days, although the French Prime Minister Manuel Valls insists they are not formally linked.

It comes as hundreds of soldiers will be deployed after two men drove vehicles at pedestrians, leaving 23 people injured.

Up to 300 troops will boost security on the streets of French cities amid heightened fears over terrorist attacks.

The announcement, by Mr Valls, came after officials stressed the attacks in Dijon and Nantes were not related and downplayed links to terrorism.

The attack in Dijon on Sunday injured 13 people when a car driver targeted pedestrians in five different parts of the city in the space of half an hour.

He was heard shouting "God Is Great" in Arabic, before ploughing into pedestrians. Prosecutors said the attacker had been hospitalised 157 times, stressing that he was mentally ill.

The attack in Nantes on Monday left 10 people hurt when a van was driven into a Christmas market in the city.

A government minister said the attack "seems to be that of an unbalanced mind".

The disturbances followed the stabbing of three police officers in Tours on Saturday. The man, who also shouted 'God is Great' in Arabic, was eventually shot dead by officers

Mr Valls told Europe 1 radio there were no indications the rampages in Nantes and Dijon were linked.

But he noted the rising profiles of French extremists in Syria and said the terrorist threat is higher than ever.

In a live television address he said: "The number of patrols will be increased during this (Christmas) period. Two hundred to 300 soldiers will be deployed in the coming hours."