Europe was on high alert on Monday as the suspected mastermind of a jihadist cell in Belgium remained at large and authorities blocked anti-Islamist rallies in Germany and France.

In the wake of the deadly attacks in France and anti-terror raids in Belgium, EU foreign ministers were scheduled to meet in Brussels to discuss ways to boost cooperation to combat the threat posed by radicalized Europeans returning home after fighting in Iraq and Syria.

The meeting on Monday came as the bloc prepares for a special leaders' summit on Feb 12 dedicated to fighting terrorism.

With tensions heightened, the second gunman in the attack on Charlie Hebdo magazine that killed 12 people was buried discreetly in an unmarked grave near Paris late on Saturday in the hope that it would not become a pilgrimage site for radical Islamists.

Abdelhamid Abaaoud, considered the brains behind the cell plotting to kill Belgian police, was still on the run days after the group was dismantled by intelligence services.

But the investigation appeared to be progressing with Belgian federal prosecutors announcing they would seek the extradition of a suspect arrested in Athens on Saturday "who could be linked" to the cell.

In Germany, police banned a rally by the anti-Islamic Pegida movement and other open-air gatherings planned for Monday in the eastern city of Dresden, saying there was a "concrete threat" of an attack against its leadership.

The group claimed the threat came from the Islamic State group based in Syria and Iraq, with local media reporting that Pegida's most prominent leader Lutz Bachmann was the target.

The Pegida marches have grown steadily since they began in October and drew a record 25,000 people on Jan 12 in the wake of the Paris attacks that left 17 people dead.

The anti-Islamic rallies have spread to other European countries as well.

Another caricature

Cherif Kouachi, one of two brothers who attacked satirical weekly Charlie Hebdo on Jan 7, was buried in Gennevilliers, a day after the funeral of his older brother Said in the northeastern city of Reims.

The brothers were shot dead by police after a three-day manhunt following their attack on Charlie Hebdo, which had enraged many Muslims around the world with its repeated publication of cartoons lampooning the Prophet Muhammad.

Anger erupted in a string of majority Muslim countries after the magazine responded to the attack by running another caricature last week, showing the prophet under the headline "All Is Forgiven".

AFP - Reuters