AMSTERDAM, Netherlands (AP) _ A man pleaded guilty Tuesday to slashing a painting of American abstract expressionist Barnett Newman in 1997, but said he was mentally unfit at the time.

``He said he suffers from schizophrenia and was psychotic,'' said Jan Merton, a spokesman for the Amsterdam District Court. ``It is now up to the three judges to decide how responsible he is for his actions.''

The defendant, Gerard van Bladeren, was charged with taking a switchblade knife to the painting ``Cathedra'' in Amsterdam's Stedelijk Museum, slicing the canvas several times.

A verdict is due within two weeks.

More than 11 years ago, Van Bladeren was found guilty of carving ``Who's Afraid of Red, Yellow and Blue III,'' another Newman piece, also in the Stedelijk Museum. He served a short jail sentence and was banned from the museum for three years.

At the time, Van Bladeren proclaimed himself a misunderstood artist and denounced the art establishment. He said he considers destroyed abstract paintings as works of art.

On Tuesday, Van Bladeren repeated his dislike for abstract artwork, but added that he regrets the action.

``Cathedra,'' a blue monochrome work from 1951, has been in the museum's permanent collection since 1975. The painting's value was not released.