At least 11 people have been killed after two gunmen attacked the Paris office of French satirical magazine Charlie Hebdo, French media report.

Witnesses spoke of sustained gunfire at the office as the attackers opened fire with Kalashnikov assault rifles. According to some reports, two of the victims were police officers.

Charlie Hebdo, a satirical weekly, has courted controversy in the past with its depiction of news and current affairs.

The magazine’s latest tweet was a cartoon of the Islamic State militant group leader, Abu Bakr al-Baghdadi.

Charlie Hebdo was fire-bombed in November 2011 a day after it carried a caricature of the Prophet Muhammad.