One person was shot dead and three police officers were wounded at a freedom of speech debate in Denmark’s capital Copenhagen where the French ambassador was speaking.
Two gunmen are said to be still at large.
Reports say up to 40 shots were fired outside the venue in the Danish capital.
Controversial Swedish cartoonist Lars Vilks, who has drawn caricatures of the Prophet Muhammad, was also present at the blasphemy debate.
Shortly after the attack, a message appeared on the Twitter feed of French ambassador Francois Zimeray saying he was unharmed.
The area around the venue, reportedly a cafe, is under lockdown.
Lars Vilks stoked controversy in 2007 by drawing pictures of the Prophet Muhammad dressed as a dog.
An organizer of the event, Helle Merete Brix, said she clearly considered the incident as an attack on Lars Vilks, reported the Associated Press.
In 2010 two brothers tried to burn down Lars Vilks’ house in southern Sweden and were imprisoned for attempted arson.
