paris attack police may
© ReutersPolice guard the scene of a knife attack in Paris, France May 12, 2018
The French government defended its anti-terrorism measures over the weekend after it turned out that the perpetrator of a deadly knife attack in Paris was on a state security watchlist.

Government spokesman Benjamin Griveaux said the man, a naturalized French citizen who was born in Chechnya in 1997, had been on the watchlist since 2016.

It was the second deadly attack in two months by a person flagged on the watchlist, and the conservative opposition renewed calls for people on the list to be detained or deported.

Griveaux said security forces had foiled 22 attacks over the past 15 months.

"When we live through a tragedy like yesterday, it is visible," Griveaux told broadcasters LCI and RTL. "What's unfortunate is that our successes, by definition, are invisible."

The attack was claimed by Islamic State. French authorities have not confirmed any link with the organization but are treating the incident as a terrorist attack.

A video emerged Sunday online purporting to show the attacker swearing allegiance to Islamic State leader Abu Bakr al-Baghdadi.

In the video, the speaker, wearing a mask that covers most of his face, calls on "my brothers the mujahedeen" in French with scattered Arabic phrases.

In terms typical of Islamic State's propaganda, he calls on Muslims in Europe to try to move to the group's now much-reduced territory, or, failing that, to commit attacks at home.

The video, which appeared to have been published by Islamic State's news agency, Amaq, could not be verified.

The attack near the Paris Opera Saturday night killed a 29-year-old man. Four other people were injured, two of them seriously.

The attacker was shot dead by police, who arrived on the scene within minutes.

Both seriously injured people were out of danger by midday Sunday, a source close to the investigation said.

The attack took place in a busy area with several theaters and many bars and restaurants.

"It is, once again, a way of life, our way of life, which has come under a cowardly attack," Griveaux said.

The attacker's parents and a friend were detained for questioning, according to a judicial source.

The revelation that the perpetrator was on the state security watchlist - known as the "S file" - drew an angry reaction from the right and far-right opposition.

In March, a man on the watchlist killed four people in a series of attacks in southern France, including a senior police officer who surrendered to him in return for the freeing of a civilian hostage.

The leader of France's biggest opposition party renewed his call on President Emmanuel Macron to detain "the most dangerous individuals" on the watchlist and expel all foreigners listed on it.

"There is no longer room, Mr. President, for this blind inaction which has lasted too long," Laurent Wauquiez of the conservatives Les Republicains said in a statement.

"What use can this S file be if we don't use it to ensure that these time bombs cannot do any harm on French soil?" National Front leader Marine Le Pen wrote on Twitter.

But Griveaux argued: "Unfortunately, there is no way of stopping this sort of incident from happening."

The security watchlist was a key tool for police and intelligence services, he said, arguing that experts were opposed to using it as a basis for roundups or deportations.

"If you lock them up then, again, you won't be able to tease out their networks and dismantle operations that could take place tomorrow," Griveaux said.

Source: Deutsche Presse-Agentur GmbH