Dutch far-right politician Geert Wilders said Sunday he was "shocked" by the shooting outside a Prophet Mohammed cartoon contest in Texas that he attended.

"I am shocked. I just spoke for half an hour about the cartoons, Islam and freedom of speech and I had just left the premises," he said in an email to AFP, adding that the shooting was an attack on "liberties".

Two suspects were killed and a police officer was injured in the shooting outside the contest, organizers reported.