PARIS: French Embassy in Niger warned French citizens to stay indoors Saturday as violent protests against publication of anti-Islam cartoon by the French weekly Charlie Hebdo spread in the capital Niamey.

“Be very cautious, avoid going out,” the embassy said on its website.

A violent mob torched three churches in Niger’s capital Niamey Saturday during fresh protests against the magazine.

Around 1,000 youths wielding iron bars, clubs and axes rampaged through the city, hurling rocks at police who responded with tear gas in a second day of violent demonstrations against the anti-Islam publication.

Some 15,000 people also rallied in Russia’s Muslim North Caucasus region of Ingushetia against Charlie Hebdo.

Meanwhile, jittery European nations stepped up security in the wake of last week’s attacks in France that claimed 17 lives, including 12 at Charlie Hebdo’s offices.

Belgium began deploying hundreds of armed troops to patrol the streets after security forces smashed a suspected “terrorist” cell planning to kill police officers.

And in London, authorities were mulling “further measures” to protect police “given some of the deliberate targeting of the police we have seen in a number of countries across Europe and the world,” said Mark Rowley, head of counter-terrorism for the British police.

British police officers, for the most part unarmed, might be equipped with taser guns as part of reinforced security measures, according to the local press.

Traffic was suspended in the Channel Tunnel between France and Britain after smoke was spotted, but there was no immediate indication if there was a link to recent attacks.

French and Belgian authorities were grilling suspected accomplices both of the Paris gunmen and the alleged “terrorist” cell raided in eastern Belgium.

Belgian police were hunting for the suspected mastermind of the cell, a notorious 27-year-old militant who spent time in Syria and who may have prepared the foiled attack from bases in Greece and Turkey, according to local media.

Said Kouachi, one of the militant’s brothers who gunned down 12 people at Charlie Hebdo’s offices before being cut down by security forces in a siege, has already been buried in secret, it emerged on Saturday.

He was buried Friday in the eastern city of Reims, where he lived for around two years, under heavy police protection and with a handful of family members present, according to a well-informed source.

His grave was unmarked and the name of the cemetery not divulged. His brother Cherif was expected to be buried soon in the Paris suburb of Gennevilliers.

The mayor of Reims, Arnaud Robinet, said he was forced by law to accept the burial but was initially opposed to the gunman being buried in his city.

Said Kouachi’s wife decided not to attend the burial, in order to keep it secret, said her lawyer Antoine Flasaquier.