Security is tight as the editor of French satirical magazine Charlie Hebdo makes his way to the office Thursday morning.

The magazine recently published cartoons that ridiculed the Prophet Mohammad, including portraying him naked.

The drawings have risked exacerbating an ongoing crisis, as protests continue worldwide condemning a U.S. produced film seen as insulting to Islam.

Charlie Hebdo's lawyer defended the magazine on Thursday saying its publishers always insisted on their right to poke fun at all symbols of political and religious authority in the name of freedom of expression.

The French government had urged the weekly not to print the cartoons.

It also said it would shut embassies and schools in 20 countries on Friday as a precaution - as this is when protests sometimes break out after Muslim prayers.

Charlie Hebdo is no stranger to controversy.

Its Paris offices were firebombed last November after it published a mocking caricature of the Prophet.