A known radical Islamist was arrested on suspicion of attempting to murder a French soldier yesterday, after DNA discovered on a juice bottle was used to identify him.

Images of the 22–year-old man stabbing Cedric Cordiez, 23, in the throat and neck whilst on anti-terrorist patrol in the La Defense district of Paris on Saturday are also believed to have been used to identify him.

France has been on a security alert since January, when its troops began fighting al-Qa'ida-linked Islamists in Mali.

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The suspect was arrested outside the house of a friend after armed anti- terror police raided his home during the early hours of yesterday morning in La Verriere, a commuter town near Versailles. He was reportedly caught on camera saying a Muslim prayer in the corner of a shopping mall ten minutes before the attack was carried out.

The man, who is unemployed and homeless, has been identified by police as Alexandre Dhaussy. French state prosecutor Francois Molins said the suspect was already known to authorities for crimes such as theft and possession of firearms and that he converted to Islam as an adult.

Under French anti-terrorism law, Dhaussy can be held without charge for 96 hours. Molins told a news conference: "The nature of the incident, the fact it took place three days after London, and the prayer just before the act lead us to believe he acted on the basis of religious ideology and that his desire was to attack a representative of the state."

Police later said Dhaussy had previosuly been identified by intelligence services for showing some signs of radicalisation, but had not been considered dangerous and was not monitored any further.

He had, for instance, refused a job in 2011 that would mean he had to work alongside women and had been checked by police in 2012 for acting suspiciously and not wanting to wait for a bus with women, police said.

In Britain, the killing of Lee Rigby in what the Government said appeared to be a terrorist attack has led to protests against radical Islam and fears of a possible anti-Muslim backlash. There have been fears that this may have been a copycat attack.

"This incident comes at a time of concern, threats, terrorist threats that this country has been receiving for the past few months. So we have to remain alert," Interior Minister Manuel Valls said on the iTele network of the Paris stabbing.

Mr Cordiez is said to be recovering from his injuries and was released from hospital on Monday.