Dutch authorities have announced a fresh arrest in Tuesday's murder in Amsterdam of controversial filmmaker and Islam critic Theo van Gogh.

Police say they arrested the 23-year-old suspect of Moroccan origin Friday. They also say they seized computers and video cassettes from his Amsterdam residence. Authorities have now detained nine suspects, but they have released two.

The government Friday announced new measures against Islamic extremists. These include stripping criminals with dual citizenship of their Dutch nationality and boosting police powers.

A letter left on the filmmaker's body contained death threats against Dutch lawmaker Ayaan Hirsi Ali, who had worked with Mr. van Gogh on a film about the abuse of Muslim women.

Several hundred people of Moroccan descent marched through The Hague Saturday to denounce the killing and urge peaceful co-existence between Muslims and others.

Some information provided by AP, Reuters and AFP.