Police at a news conference display a picture of the man arrested on suspicion of sexual abuse on up to 50 children.

Police at a news conference display a picture of the man arrested on suspicion of sexual abuse on up to 50 children.

A man who worked for at least two preschools is feared to have molested dozens of young children and used them to make child pornography in one of the worst cases of sexual abuse in the Netherlands.

Amsterdam's mayor, Eberhard van der Laan, said more than 50 parents were informed on Sunday that a 27-year-old suspect arrested last week had either confessed to abusing their children or was thought to have done so.

''This is about a serious suspicion of grave abuse by a man who was arrested Tuesday and has been held since then,'' Mr Van der Laan said at a news conference together with the city's police commissioner and chief prosecutor.

''I see it as my most important job to inform parents as well as possible.''

The suspect was arrested on December 7, after a police television program aired an image of a victim that US authorities had seized in a separate child pornography investigation, police chief Herman Bolhaar said.

US law enforcement officials had informed Dutch authorities they believed the image had been made in the Netherlands.

The victim's parents identified their child from the image on television and called police, leading to the suspect's arrest the same night, Mr Bolhaar said.

The man's computers containing child pornography were seized and he has since confessed to dozens of sex crimes allegedly committed over the past year and a half, Mr Bolhaar said. The man worked at at least two day-care centres in Amsterdam and also offered his services online as a babysitter.

Mr Van der Laan urged media not to photograph children possibly affected and to be reserved in contacting parents.

The man was identified as a Dutch citizen originally from Riga, Latvia. He got the Dutch nationality after a gay marriage, but police published his photo - an unusual step, as privacy laws usually prevent publication of photographs of suspects in the Netherlands.

Mr Van der Laan said the photo had been released in part to reassure the thousands of parents in Amsterdam whose children were not affected.

''At the same time we want to alert others that it indeed was their babysitter,'' he said.

Prosecutors said in a statement they had also arrested the man's 37-year-old partner on suspicion of possession of child pornography. The older man is not suspected of physically molesting children, the statement said.

A 39-year-old employee of one of the day-care centres where the man worked was also arrested on Sunday after allegedly attempting an ''indecent'' online chat, the prosecution statement said.

Mr Bolhaar said there may be more victims and more suspects.

On Sunday a candle was left on the steps of Jenno's Stuffed Animal Paradise, one of the day-care centres affected. An attached note bore a single word: ''Terrible.''