UN Secretary General Ban Ki-moon has expressed outrage over the "cold-blooded" and "unjustifiable" terrorist attack against French magazine Charlie Hebdo, with the UN Security Council underlining the need to bring perpetrators of terrorism to justice.

The UN Chief and the powerful Security Council were joined by other UN bodies and the President of the General Assembly in strongly condemning the attack that killed 12 people, including the top editor, prominent cartoonists and police officers.

"I want to express my outrage at the despicable attack today against the French magazine Charlie Hebdo. It was a horrendous, unjustifiable and cold-blooded crime," the UN Chief said.

"This act of violence can in no way be justified. This is an attack against freedom of expression and freedom of the press - the two pillars of democracy," Moon said.