France's prime minister demanded tougher anti-terrorism measures Tuesday after deadly attacks that some call this country's Sept. 11 — and that may already be leading to a crackdown on liberties in exchange for greater security.

Police told The Associated Press that the weapons used came from abroad, as authorities in several countries searched for possible accomplices and the sources of financing for last week's attacks on the satirical newspaper Charlie Hebdo, a kosher market and police. A new suspect was identified in Bulgaria.

"We must not lower our guard, at any time," Prime Minister Manuel Valls told Parliament, adding that "serious and very high risks remain."

Lawmakers in the often argumentative chamber lined up overwhelmingly behind the government, giving repeated standing ovations to Valls' rousing, indignant address — and then voted 488-1 to extend French airstrikes against Islamic State extremists in Iraq.

"France is at war against terrorism, jihadism, and radical Islamism," Valls declared. "France is not at war against Islam."

He called for increased surveillance of imprisoned radicals and told the interior minister to quickly come up with new security proposals.

French police say as many as six members of the terrorist cell that carried out the Paris attacks may still be at large, including a man seen driving a car registered to the widow of one of the gunmen. The country has deployed 10,000 troops to protect sensitive sites, including Jewish schools and synagogues, mosques and travel hubs.

Several people are being sought in connection with the "substantial" financing of the three gunmen behind the terror campaign, said Christophe Crepin, a French police union official. The gunmen's weapons stockpile came from abroad, and the size of it, plus the military sophistication of the attacks, indicated an organized terror network, he added.

"This cell did not include just those three. We think with all seriousness that they had accomplices, because of the weaponry, the logistics and the costs of it," Crepin said. "These are heavy weapons. When I talk about things like a rocket launcher — it's not like buying a baguette on the corner. It's for targeted acts."

Speaking to legislators in London, the head of the European police agency Europol, Rob Wainwright, said that 3,000 to 5,000 European nationals have gone to fight in the Mideast, calling it a "startling figure" and "the most serious threat Europe has faced since 9/11."

He urged better intel sharing, saying later to the BBC: "The way the network is diffuse in nature, not homogenous, not centralized, but a gathering of thousands of independent and semi-independent actors makes it very, very difficult for the security agencies to monitor it wholesale."

In a sign that French judicial authorities were using laws against defending terrorism to their fullest extent, a man who had praised the terror attacks while resisting arrest on a drunk driving violation was swiftly sentenced to four years in prison.

While the attacks have left France in jitters, some warned against going as far as a French version of the U.S. Patriot Act passed after Sept. 11.

"This must not lead to the renouncing of fundamental freedoms, otherwise we prove right those who come to fight on our soil," former Prime Minister Francois Fillon said on France-Inter radio.

The investigation spread to yet another country: A Bulgarian prosecutor announced that a Frenchman jailed since Jan. 1 had ties to Cherif Kouachi, one of the brothers who carried out the Charlie Hebdo attack.

The man, identified by French prosecutors as Joachim Fritz-Joly, was arrested as he tried to cross into Turkey. He was facing two European arrest warrants, one citing his alleged links to a terrorist organization and a second for allegedly kidnapping his 3-year-old son and smuggling him out of the country, said Darina Slavova, the regional prosecutor for Bulgaria's southern province of Haskovo.

"He met with Kouachi several times at the end of December," Slavova said. The child was sent back to his mother in France.

At a hearing in Haskovo on Tuesday, authorities decided to keep Fritz-Joly in custody until another hearing to determine whether he will be extradited to France. The Frenchman told the court he had known Cherif Kouachi since childhood.

"A man can have friends and they can do whatever they want, but I am simply going on vacation and have nothing to do with it," he told the court.

Kouachi and his older brother, Said, killed 12 people at the satirical paper's offices on Jan. 7, while their friend, Amedy Coulibaly, killed a French policewoman Thursday and four hostages Friday in a Paris kosher grocery. All three claimed ties to Islamic extremists in the Middle East — the Kouachis to al-Qaida in Yemen and Coulibaly to the Islamic State group.

All three gunmen died Friday in clashes with French police.

Authorities were searching around Paris for the Mini Cooper registered to Hayat Boumeddiene, Coulibaly's widow, who Turkish officials say is now in Syria. French police also sought the person or persons who filmed and posted a video of Coulibaly explaining how the attacks in Paris would unfold.

Earlier Tuesday, in ceremonies thousands of miles apart, France and Israel paid tribute to the victims of the terror attacks.

At police headquarters in Paris, French President Francois Hollande placed Legion of Honor medals on the flag-draped caskets of the three police officers killed in the attacks.

France will be "merciless in the face of anti-Semitic, anti-Muslim acts, and unrelenting against those who defend and carry out terrorism, notably the jihadists who go to Iraq and Syria," Hollande vowed.

A ceremonial unit of the New York Police Department, including Muslim officers, was among those attending the service for the slain officers.

As Chopin's funeral march played and the caskets were led from the building, a procession began in Jerusalem for the four Jewish victims at the kosher store.

Defying the bloodshed and terror of last week, a caricature of the Prophet Muhammad was to appear Wednesday on the cover of the latest issue of Charlie Hebdo, weeping and holding a placard with the words "I am Charlie."

Criticism and threats immediately appeared on militant websites, with calls for more strikes against the newspaper and anonymous threats from radicals, according to the SITE Intelligence Group, a U.S.-based terrorism monitor.

Charlie Hebdo, which lampoons religion indiscriminately, had received threats after depicting Muhammad before.