AMSTERDAM (AP) — A man rammed a van into the Amsterdam headquarters of one of the Netherlands' major national newspapers before setting the vehicle alight Tuesday, in an attack that the Dutch prime minister called "a slap in the face of a free press and Dutch democracy."

No one was injured in the pre-dawn attack on the De Telegraaf building. The newspaper released video of the attack on its website, showing a man ramming a white van into the building twice, before walking out and setting the vehicle on fire. He then moved away and drove off in a waiting car.

Prime Minister Mark Rutte said that a lot remained unclear about those behind the attack, but "we are alert and police are doing everything they can to catch the perpetrator(s)."

Chief editor of De Telegraaf newspaper Paul Jansen said early Tuesday that "we will not be intimidated" and said that "it is clear that we don't have friends everywhere."

Police are seeking witnesses to the incident, which happened around 4:00 am (0200 GMT).

Another media outlet, Panorama, was attacked last week with an anti-tank weapon. One suspect was detained.