The man suspected of killing two police employees near Paris claimed the act in a video posted online by one of the Islamic State extremist group's media arms, Aamaq, police said Tuesday.

In the video allegedly recorded in the victims' home, the man, named as 25-year-old Larossi Abballa, said he had "just killed the policeman, I have just killed his wife."

"I am surrounded by police at this moment," he said, exhorting others to commit similar acts of violence.

Abballa is under investigation for terrorist-affiliated murder, French prosecutor Francois Molins said at a press conference.

He was killed by French security forces when they raided the police house where he was holed out with the couple's 3-year-old son.

The suspect, who Molins said posted a 12-minute Facebook video during the attack and told police that he had pledged allegiance to the Islamic State group three weeks prior, had already been part of a judicial inquiry opened in February for links to a network encouraging travel to Syria and the surrounding zone.

But Molins said that despite the authorities intercepting Abballa's phone, there had not been specific mention of Monday's attack that would have warranted an arrest prior to the deadly stabbings.

Abballa arrived at the police commander's home in the town of Magnanville, 50 kilometres west of Paris, and knifed him outside his door just after after 8 pm [1800 GMT], Molins said. The commander worked for police forces in Les Mureaux, and his companion, a 36-year-old woman, was an administrator in Mantes-la-Jolie.

She was also killed in the house. The couple's son survived and was taken to hospital in a state of shock, Molins said.

During the video published by Amaq, Abballa pledges allegiance to Islamic State leader Abu Bakr al-Baghdadi. In the recording, which is laced with religious references, Abballa calls in French and Arabic for killings to continue - singling out journalists, politicians and rap musicians - and threatens French authorities.

He also makes unspecified threats about the European football championship, currently underway in France.

According to the SITE monitoring group, which tracks extremist activity online, Islamic State said on Amaq that Abballa was one of its soldiers.

Three men, aged 27, 29 and 44, were detained Tuesday in relation to the killings, Molins said.

French President Francois Hollande said that vigilance would be at its highest level, saying that additional measures would be taken to ensure security. After meeting with ministers earlier at the Elysee for an emergency cabinet meeting, Hollande had said the attack was "an act of incontestable terrorism."

Aside from the most recent investigation, Abballa had been long known to French authorities. He was put into provisional detention in 2011 for links to a Pakistani-Afghan extremist network, and was sentenced in 2013 to a three-year partially suspended imprisonment for association with terrorism, Molins said. But Abballa did not serve additional time after the ruling, having already been jailed.

Molins said that Abballa's prison guards noted that he had proselytized Islamist radicalism while in jail.

Interior Minister Bernard Cazeneuve said after the emergency cabinet meeting that since the beginning of the year, more than 100 people had been arrested who represented a threat to France's security.

Cazeneuve added that the threat of terrorism was "elevated in France, elevated in Europe and elevated in the West, as we have seen with the events that took place 48 hours ago in the US."

On Sunday, the lone gunman who killed 49 people in a gay nightclub in Orlando, Florida, pledged allegiance to Islamic State in an emergency call while the attack was under way.

Related stories

Three detained in France for connection to police killings

France mourns police couple killed by alleged extremist

State of emergency extended in France

Latest news

Syrian opposition rules out future role for President al-Assad

The Syrian opposition said Friday it would not accept any role for President Bashar al-Assad in the future of the war-torn country, reacting to a recent US shift saying that removing al-Assad is no longer a priority for Washington.

Russian Army integrates breakaway forces of Georgian province

Parts of the small fighting forces of the Georgian breakaway province of South Ossetia have been placed under Russian military control, Russian Defence Minister Sergei Shoigu said on Friday.

Czech Republic's Pilsner Urquell beer is now Japanese

Japanese brewing company Asahi completed its takeover of the Czech brewery Pilsner Urquell on Friday, Asahi said in a statement.

Judge approves 25-million-dollar settlement of Trump University case

A US district judge on Friday approved a 25-million-dollar settlement of lawsuits and state fraud allegations against Trump University, the US president's now-defunct business venture.

Former Thai premier Thaksin to junta on reconciliation: 'Cut me out'

Former Thai prime minister Thaksin Shinawatra on Friday announced that he is not interested in the junta-led reconciliation process, three days after the junta handed him a half-a-billion-dollar tax bill for his past business deal.

Dalic: We welcome possible deal between Agrokor and banks

The government welcomes the possibility of an agreement being concluded between the Agrokor food company and creditor banks, and the bill on vitally important companies is not a fallback plan but the result of the government's care for the overall economic and financial stability of Croatia, Deputy Prime Minister and Minister of Economy Martina Dalic told a press conference in Zagreb on Friday.

Croatia, China sign action plan for cooperation in agriculture

The Croatian and Chinese ministries of agriculture on Friday signed an action plan for cooperation in the field of agriculture for the period 2017-2018, the Croatian ministry said in a statement.

ZSE indices up, Agrokor shares in focus of investor interest

The Zagreb Stock Exchange (ZSE) indices on Friday rose by more than 1.8%, with stocks of the Agrokor food and retail concern being in the focus of investor interest again.

Berlin police defend handling of Berlin market attacker

Berlin police defended themselves on Friday against accusations that they stopped surveillance on Berlin Christmas market attacker despite knowing in June 2016 he was dangerous.

Croatia, creditors tailor emergency measures to save tottering giant

Croatia's tottering retail and food giant Agrokor reached an agreement with its creditors, putting its debts standby and allowing it to continue working during emergency restructuring, the Croatian branch of Austria's Erste Bank said Friday.

Agrokor's creditors say standstill agreement to go into force today

A standstill agreement regarding the Agrokor concern's existing financial obligations to banks will take effect on Friday, additional capital will be injected into the concern in the coming days and the concern will be actively restructured, which includes a change of its management, it was said on Friday after a meeting between Agrokor's suppliers and creditor banks.

Palestinians, UN slam Israel's new settlement plan

Palestinians, Israeli activists and the UN lambasted the government of Israeli Prime Minister Benjamin Netanyahu on Friday, a day after it gave the go-ahead for the first new West Bank settlement in a quarter of a century.

South Sudan rebels release three abducted foreign oil workers

South Sudanese rebels have released three foreign engineers they abducted in early March in the oil-rich Upper Nile region, Foreign Affairs Ministry official Mawein Makol Arik said on Friday.

Turkish opposition: Imprisoned party chief has gone on hunger strike

The head of Turkey's pro-Kurdish opposition party has launched a hunger strike from prison.

European leagues threaten Champions League schedule clashes

The European Professional Football Leagues (EPFL) on Friday threatened schedule clashes on Champions League matchdays in an ongoing dispute with the governing body UEFA.

Danish court revokes citizenship of IS volunteer

A Danish appellate court on Friday stripped a man of his Danish citizenship for volunteering to fight for the extremist Islamic State in Syria.

Banks and Agrokor agree on key elements of standstill agreement

Member banks of the coordinating committee of financial creditors and representatives of the Agrokor food company have in principle agreed on key elements of a standstill agreement, which is expected to be signed later today, announcing changes in the company's management team, Erste Bank said in a statement on Friday afternoon.

Syrian man on trial in Sweden; mosque attack labelled terrorism

A Syrian man went on trial Friday in the southern Swedish city of Malmo, charged with terrorism and arson after an attack last year on a building used as an assembly hall by Shiite Muslims.