French police questioned on Sunday relatives of one of the suicide attackers who brought carnage to Paris as a row over Europe's refugee crisis reignited, with conservatives demanding an end to "the days of uncontrolled immigration".

Paris prosecutor Francois Molins told reporters that three jihadist cells staged coordinated hits on Friday night at bars, a concert hall and soccer stadium, killing 129 people and injuring 352, including 99 who were in a serious condition.

Prosecutors have said the slaughter — claimed by Islamic State as revenge for French military action in Syria and Iraq — appeared to involve a multinational team with links to the Middle East, Belgium and possibly Germany as well as home-grown French roots.

Belgian prosecutors said two of the gunmen were French nationals who had been living in Brussels. They also said they had arrested seven people in the Belgian capital. Police staged raids on Saturday in Molenbeek, a poor, immigrant quarter.

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In a sign that at least one gunman might have escaped, a source close to the investigation said a Seat car believed to have been used by the attackers had been found in the eastern Paris suburb of Montreuil with three Kalashnikov rifles inside.

A local resident told a Reuters cameraman that police had cordoned off the area around the car around midnight and brought in an anti-explosives vehicle in case it was boobytrapped. The car was taken away after the guns had been removed.

One attacker appears to have arrived in Europe alongside Syrian refugees, seeking asylum in Serbia. But with the European Union deeply split over the migrant crisis, European Commission head Jean-Claude Juncker stressed the attacker was not a refugee but a criminal.

Museums and theaters remained closed in Paris for a second day on Sunday, with hundreds of soldiers and police patrolling the streets and metro stations after French President Francois Hollande declared a state of emergency.

Seven gunmen, all of whom were wearing suicide vests packed with explosives, died in the multiple assaults. The first to be identified was named as Ismael Omar Mostefai, a 29-year-old who lived in the city of Chartres, southwest of Paris.

French media said he was French-born and of Algerian descent. Molins said the man had a security file for Islamist radicalization, adding that he had a criminal record but had never spent time in jail. He was identified through tests on his severed finger.

A judicial source said Mostefai's father and brother had been taken in for questioning, along with other people believed to be close to him.

"PARIS CHANGES EVERYTHING"

One of the attackers seems to have followed the route taken by hundreds of thousands of asylum seekers who have crossed by boat from Turkey to the Greek Islands, before heading for EU countries to the north, mainly Germany and Sweden.

The Serbian government said the holder of a Syrian passport found near the body of one of the gunmen had passed through the country last month. The Interior Ministry said the man, whom it identified only by the initials A.A., had been registered at Serbia's Presevo border crossing with Macedonia on Oct. 7.

It said his details were the same as those of a man who had registered in Greece on Oct. 3. Greek authorities said on Saturday the passport matched one used by someone who had landed on the island of Leros. They believe that another of the assailants may also have passed through Greece with Syrian refugees fleeing the country's civil war.

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The attacks have reignited a row within the EU on how to handle the flood of asylum seekers from Syria and other countries in the Middle East, Africa and Asia.

Top Polish and Slovak officials have poured cold water on an EU plan to relocate asylum seekers across the bloc, saying the violence underlined the concerns of Europeans about taking in Muslim refugees.

But Juncker said EU states should not give in to base reactions. "The one responsible for the attacks in Paris... he is a criminal and not a refugee and not an asylum seeker," he told a news conference on the sidelines of a G20 summit of world leaders in Turkey. [nL1N13A0AI]

Nevertheless, Bavarian allies of German Chancellor Angela Merkel called for a reversal of her "open-door" refugee policy, saying the attacks underlined the need for tougher measures to control the influx of migrants. [nL8N13A0F7]

"The days of uncontrolled immigration and illegal entry can't continue just like that. Paris changes everything," Bavarian finance minister Markus Soeder told Welt am Sonntag newspaper. Most asylum seekers entering Germany have done so through the southern state.

In Vienna, Iraqi Foreign Minister Ibrahim al-Jaafari said his country's intelligence services had shared information they had which indicated that France, the United States and Iran were among countries being targeted for attack.

At the G20 summit, U.S. President Barack Obama vowed to step up efforts to eliminate Islamic State in Syria and prevent it from carrying out attacks like those in Paris, while European leaders urged Russia to focus its military efforts on the radical Islamists. [nL8N13A0M7]

France was the first European state to join U.S. air strikes against Islamic State targets in Iraq in September 2014, while a year later it extended its air strikes to Syria. Russia began its own air campaign in Syria in October, but has been targeting mainly areas controlled by other groups opposed to its ally, President Bashar al-Assad, Moscow's critics say.

YOUNG VICTIMS

The names of the first victims have started to filter out on social media, many of them young people who were out enjoying themselves on a Friday night. The dead included one U.S. citizen, one Swede, one Briton, one German, two Belgians, two Romanians and two Mexicans, their governments said.

In the worst carnage, three gunmen killed at least 89 people at a rock concert by an American band at the Bataclan theater before detonating explosive belts as commandos launched an assault.

Members of the U2 rock group laid flowers at a makeshift memorial near the hall, including its singer, anti-poverty campaigner Bono. The Irish band had been due to perform in Paris on Saturday, but canceled the concert following the attacks.

It was the deadliest attack in France since World War Two and the worst in Europe since the Madrid train bombings of 2004, in which Islamists killed 191 people.

Quoting an unnamed senior official, Israeli television said Israel's spy services saw a "clear operational link" between the Paris mayhem, suicide bombings in Beirut on Thursday, which killed 43, and the Oct. 31 downing of a Russian airliner over Egypt, where 224 people died.

France had been on high alert since Islamist gunmen attacked the satirical weekly Charlie Hebdo and a kosher supermarket in Paris in January, killing 18 people.

Those attacks briefly united France in defense of freedom of speech, with a mass demonstration of more than a million people. But far-right populist Marine Le Pen is now making gains by blaming France's security problems on immigration and Islam.