Four bookshops in Brussels have received letters warning of reprisals if they distribute the controversial first issue of French satirical weekly Charlie Hebdo since last week's attacks, Belgian authorities said.

Copies of the satirical magazine, featuring the Prophet Mohammed on its cover holding a "Je Suis Charlie" sign under the headline "All is forgiven", are due to go on sale in Belgium on Thursday.

French Islamist gunman Amedy Coulibaly bought most of the weapons used in last week's Paris attacks in Belgium, Belgian newspapers reported Wednesday.

The Kalashnikov rifle and rocket launchers used by brothers Said and Cherif Kouachi in the Charlie Hebdo magazine attack were bought by Coulibaly near the Gare du Midi railway station for less than 5,000 euros ($7,000), Flemish newspaper Het Laatste Nieuws reported.

The offices of a Belgian newspaper that republished cartoons from the French satirical magazine Charlie Hebdo were evacuated on Sunday after receiving an anonymous bomb threat, its staff said.

The evacuation of Le Soir, a French-language daily, came as thousands of people marched through Brussels in solidarity with France following Islamist attacks on Charlie Hebdo and other sites.

Tens of thousands of people rallied worldwide in solidarity with France on Sunday, with marchers across Europe and the Middle East chanting "Je suis Charlie" and holding pens in the air.

From Berlin to London and Jerusalem to Beirut, crowds waved French flags and sang the anthem La Marseillaise following the Islamist attacks that killed 17 people.

Governments around Europe huddled with their intelligence services Wednesday to evaluate security measures in the wake of the massacre at French satirical weekly Charlie Hebdo.

The Paris attack by heavily armed masked men shouting "Allahu akbar" (God is Greatest) was the worst in France in decades and stoked fears of a new wave of Islamist attacks in Europe.

An imprisoned Belgian serial rapist and murderer whose wish to die had been granted by doctors will not now be euthanized following a fresh medical decision, Justice Minister Koen Geens said Tuesday.

Frank Van Den Bleeken, who has spent 26 years in jail for repeated rapes and a rape-murder, will be moved from his prison in the northwestern city of Bruges to a new psychiatric treatment centre in Ghent, the minister said in a statement.

Belgian police surrounded an apartment in the city of Ghent on Monday after reports that armed men were holding a hostage, but the incident may have been a false alarm, officials said.

A French court Friday sentenced the former mayor of a small seaside village to four years in prison for concealing flood risks that led to the death of 29 people in a brutal storm.

The court ruled that Rene Marratier was aware of the risks of flooding in La Faute-sur-Mer on the western coast but "deliberately hid" them so as not to miss out on the "cash-cow" of property development.

A strike against austerity measures by Belgium's new government on Monday paralyzed public transport and caused havoc with international flights and train services in the capital.

All underground trains, buses and trams were halted in Brussels while high-speed train links to cities in France, the Netherlands and Germany were also suspended, officials said.

How do you turn around a young man who is determined to destroy the West? In the Danish city of Aarhus, you take him to a cafe or a public library and talk about football.

This is the softly-softly approach of Mads, a mentor in an innovative programme to deradicalise young Muslim men who might otherwise turn to violence.