Meanwhile, jittery European nations stepped up security in the wake of last week's attacks in France that claimed 17 lives.
Belgium began deploying hundreds of armed troops to patrol the streets after security forces smashed a suspected Islamist "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.
Meanwhile, French and Belgian authorities were grilling suspected accomplices both of the Paris gunmen and the alleged "terrorist" cell raided in eastern Belgium.
Also Read
Belgian police were hunting for the suspected mastermind of the cell, a notorious 27-year-old jihadist who spent time in Syria and who may have prepared the foiled attack from bases in Greece and Turkey, according to local media.
And fresh protests against Charlie Hebdo broke out for a second day running in Niger.
On Friday, the protesters set fire to the French cultural centre and three churches in Zinder.