A man allegedly inspired by the Islamic State fatally stabbed a couple with ties to the police in Magnanville, France, about 30 miles northwest of Paris. (James McAuley, Jason Aldag/The Washington Post)

France’s president called Tuesday for increased security in this tense nation after an apparent ­Islamic ­State-inspired attacker fatally stabbed a police officer and his partner before he was killed by police.

Authorities took three suspects into custody and said the assailant had a list of names for possible further attacks, including journalists and public officials. The names have not been made public.

President François Hollande described the killing of the couple — Capt. Jean-Baptiste Salvaing, 42, and his partner, Jessica Schneider, 36, identified as an administrative secretary at a police department outside Paris — as “undeniably a terrorist attack” and said that “France is confronted by an extremely high terrorist threat.”

The couple’s 3-year-old son was present during the attack in their home but was apparently unharmed. The attacker, identified as Larossi Abballa, 25, apparently posted a video message to a Facebook account before he was killed in a police raid on the couple’s home in Magnanville, about 30 miles northwest of ­Paris, officials said.

A French police officer lays flowers in tribute to two colleagues killed Monday in a knife attack, believed inspired by the Islamic State, near their home in Magnanville outside Paris. (Thibault Camus/AP)

A French journalist and expert on Islamist radicalism, David Thomson, said Abballa also posted a video calling for the deaths of more police officers, prison guards and journalists. French authorities later confirmed the existence of the postings.

A video released by the Amaq news agency, which is believed to be linked to the Islamic State, appears to show Abballa moments after the attack speaking in a mix of French and Arabic. In the video, he says, “I just killed a police officer and his wife.” Then he adds, “The police are currently surrounding me.”

The video appeared to have been edited, and the victims do not appear, said the SITE Intelligence Group, which monitors militant statements online.

According to Thomson, who saw Abballa’s video before it was taken down, the assailant threatened that the European Championship soccer tournament currently hosted by France “would be a graveyard.”

Originally from the Paris suburb of Mantes-la-Jolie — adjacent to Magnanville, where he murdered the police couple — Abballa had a previous terrorism conviction and ties to Pakistani radical networks. In 2013, Abballa was sentenced to three years in prison for attempting to recruit militants to fight in Pakistan. In 2015, he was subjected to court-ordered wiretaps after one of his relatives departed for Syria, Reuters reported.

Abballa’s precise motive in killing this particular couple remains unclear, although François Molins, the Paris prosecutor, told reporters Tuesday that the attacker “knew the quality of the victim’s policing.”

During negotiations with the police unit that stormed the couple’s home around midnight, Abballa said he had sworn allegiance weeks earlier to Abu Bakr al-Baghdadi, the leader of the Islamic State, according to ­Molins.

The prosecutor said Abballa also told the police unit that he was acting on Baghdadi’s directive to “kill nonbelievers with their families wherever they live.”

Within hours of the killings, the Amaq agency cited an “unnamed source” claiming that one of the group’s operatives had carried out the stabbings. The Islamic State has not formally asserted responsibility.

France has been in a state of emergency since attacks on Nov. 13, 2015, that killed 130 people across the French capital. Bernard Cazeneuve, France’s interior minister, repeated Tuesday that more than 100 people have been arrested since then for having suspected “direct links to terrorism.”

The Euro 2016 soccer tournament, which began Friday in Paris, has raised security concerns, especially after it was revealed that the same terrorist cell that attacked Paris in November and Brussels in March had initially planned to attack the ­tournament.

The government has deployed more than 100,000 security forces to police the tournament, held at venues in 10 cities across the country.

Last month, Abu Muhammad al-Adnani, a spokesman for the Islamic State, told followers to increase “lone wolf” attacks in the West during the holy month of Ramadan. “The tiniest action you do in the heart of their land is dearer to us than the biggest action by us,” he said in an audio message released by al-Furqan, the media arm of the Islamic State.

Security analysts here say that while France has significant anti-terrorism programs in place — such as government surveillance and intelligence-sharing systems — there is little that can be done against terrorists who operate individually or in small groups.

“Still there are people who can go through the process with very basic weapons, improvised weapons or things that will go underneath the intelligence surveillance,” said Jean-Charles Brisard, director of the French Center for the Analysis of Terrorism, in an interview.

The stabbings near Paris came the day after another lone attacker, Omar Mateen, 29, opened fire in a gay nightclub in Orlando, killing 49 people before he was fatally shot by police. Like Abballa, Mateen had also declared his allegiance to the Islamic State, although he may not have had any contact with the group, and his views appeared confused.