PARIS (AFP) - French police on Saturday shot dead a knife-wielding man who attacked three officers in a police station while shouting "Allahu Akbar" ("God is great").

The man wounded one officer's face at the entrance to the police station in Joue-les-Tours near the city of Tours in central France and injured two others before he was shot.

The perpetrator was a Burundi-born French national who was known to police for common crimes, a source close to the investigation told AFP.

The attacker "shouted 'Allahu Akbar' from the moment he entered until his last breath," the source said.

"It looked like the sort of act called for by Islamic State," the source said.

"The investigation is leading towards an attack... motivated by radical Islamist motives."

The Islamic State group, which has seized control of swathes of Iraq and Syria using brutal violence, has exhorted its followers to mount attacks in the West.

According to a statement by the interior ministry, the assailant was around 20 years of age, and was "killed (by) police officers present using their issued firearms."

Prime Minister Manuel Valls pledged his support for the police officers whom he described as being "seriously injured and in a state of shock".

He said the state would deal "severely" with anyone who attacked the police.

The three wounded police officers were said to be in a stable condition.

Interior Minister Bernard Cazeneuve, who visited the scene, said the police had been subjected to a "brutal attack".

He paid tribute to the "cool-headedness and professionalism shown by the police officers".

The attacker was not on any watch lists maintained by France's main domestic intelligence service, the General Directorate for Internal Security, the source involved in the inquiry said.

But the source noted the assailant's brother was known to security agencies for his radical convictions and had at one point planned to travel to Syria.

Authorities believe around 1,200 French nationals or residents are involved in jihadist networks in Iraq and Syria.

Like other European countries, France is concerned about the risk of attacks mounted by nationals who return home after fighting alongside extremists in Syria.

The main suspect in the murders of four people at Brussels' Jewish Museum in May, Mehdi Nemmouche, is a Frenchman of Algerian origin who spent more than a year fighting with extremists in Syria.

In 2012, French Islamist Mohammed Merah killed seven people in the south-west city of Toulouse.

He was killed by police after a 32-hour siege in his flat.

A year later, a 22-year-old French Muslim convert injured a soldier in the La Defense business district of Paris.