US President Barack Obama has telephoned his French counterpart Francois Hollande to express condolences over the deadly attack targeting a satirical magazine in Paris that left 12 dead, offering assistance in bringing the attackers to justice.

"President Obama called French President Hollande from Air Force One this afternoon to personally offer his condolences and to express solidarity after this morning's horrific terrorist attack in Paris," the White House said.

Obama offered the resources of the United States as France works to identify, apprehend, and bring to justice the perpetrators and anyone who helped plan or enable this terrorist attack.

"President Hollande thanked the President for his words of support and provided an update on steps being taken to care for the victims and to arrest those responsible. He affirmed that France will never waver when faced with such adversity and will continue to defend the values of freedom and tolerance that the French republic and its people so nobly embody," it said.