A suspect sought by France in the wake of the Champs Elysees attack has turned himself in to Belgian police, France's interior ministry said Friday.
"The man in the wanted notice issued by Belgian authorities presented himself to a police station in Antwerp," ministry spokesman Pierre-Henry Brandet told AFP.
Brandet told Europe 1 radio it was "too early to say" if the man was linked to Thursday night's shooting on the famous Paris boulevard, where a 39-year-old known radical shot dead a policeman and wounded two others before being killed in a shootout.
A foreign tourist was also injured in the attack.
The Islamic State group claimed the shooting, which came three days before the first round of France's presidential election on Sunday in which security is a major concern after a string of bloody jihadist assaults since 2015.
A source close to the French investigation said the 35-year-old man being questioned in Antwerp, described as "very dangerous", had been sought by Belgian police as part of a separate probe.
During a search of his home, Belgian police found weapons, balaclavas and a train ticket for France departing Thursday morning, hours before the Paris assault.
In France meanwhile, three people known to the attacker were being questioned by anti-terror police, judicial sources said.
The three were arrested during overnight raids in the eastern suburbs of Paris.
Watch: Eyewitness describes the attack
'Close the borders'
Presidential candidates Emmanuel Macron and Marine Le Pen reacted on Friday morning to the previous evening's attack on the Champs Elysees.
Le Pen called for France to close its borders in response to the attack.
"For years now, I've been saying what needs to be done," she said.
"I will say it once again [at later press conference], detail my battle plan to protect the French from this terrorist threat starting with taking back control of our national borders because terrorists come through our borders in all circumstances and with absolute peace of mind.
"That's because of Schengen, which imposed the removal of our borders and this was accepted by our political leaders for a number of years."
She said France needed to "stop being naive and handle this this with a clear head and a firm grip".
"We need to expel foreign suspects on the S-database [threat to State security], prosecute bi-national people with an S-note and strip them of their French nationality, and prosecute French people from the S-database through the use of article 411.4 for collaboration with the enemy; increase police budgets and improve their equipment," she said.
Watch: Marine Le Pen says 'we need a president who acts'
In contrast, Macron declined to "come up with an anti-terrorist platform overnight. That is simply irresponsible".
"What our assailants want is panic and for us to change our propositions and programs every day, depending on circumstances, and divide us and put on halt the presidential campaign," he said.
"What I put forward in my project is to go further and strengthen the capabilities of our territorial intelligence services, which were unravelled with the 2008-2010 reform and that was wrong.
"And we need to strengthen and improve coordination and that is why one the pledges I have made if I were elected, is to create within the first few weeks an anti-Daesh Task Force under the president's direct authority, which will be in charge of coordinating all intelligence services."
Watch: Hollande responds to Champs Elysees shooting
Prestigious Muslim body condemns attack
The prestigious Egyptian Muslim institution Al-Azhar condemned the attack in Paris, describing it as "sinful" and un-Islamic.
"Al-Azhar strongly condemns this sinful terrorist attack," the Cairo-based Sunni institution said in a statement.
"Al-Azhar affirms its categorical rejection of such terrorist acts that contradict Islamic teachings," it added.
