A calm-looking, knife-wielding man went on a horrific stabbing spree at a daycare centre in Dendermonde, Belgium Friday, killing two babies and a female worker.

The 20-year-old man also stabbed 10 other children and two other workers. All remain in hospital with serious wounds.

Distraught parents rushed to the scene and hospitals. Rescue workers spoke in shock of finding bleeding, crying toddlers inside the centre.

"This was a particularly violent attack. All the kids had multiple stab wounds on their legs, arms and all over their bodies," Dr. Ignace Demeyer, director of the local hospital, told reporters.

Earlier reports said one of the 10 children taken to hospital had died but officials have not confirmed the report.

The man, armed with several knives, arrived at the daycare on a bicycle Friday morning but it was locked. He managed to convince the staff to let him in saying he needed some information about the children, Bart Van Doorne, editor of De Morgen newspaper in Brussels said Friday.

In total, there were six adults and 18 children inside the daycare centre.

"An act of great brutality has happened here against our weakest citizens," mayor Buyse Piet said. "The whole city is united in support for the parents who are in deep grief."

VRT Radio's Philip Heymans, reporting from outside the daycare, said the man was wearing white paint on his face and black paint around his eyes. He also said the man had ginger-coloured hair and was of a slim build.

"The killer was described as a man who was not in panic, he was very calm," Heymans said. "He arrived on his bike and after he did the killing he drove away on his bike again."

The BBC's Dominic Hughes, reporting from Brussels, said the man was arrested shortly after the incident outside a grocery store.

"He was injured in the course of that arrest and is now being treated in a local hospital," Hughes told CTV's Canada AM Friday.

At a press conference Friday, Prosecutor Christian Du Four said digital photographs of the child victims were shown to parents at the hospital so that they could be identified.

Du Four did not name the suspect but said he had no criminal history.

Doorne said the man had a history of mental problems and visited a psychiatric hospital near Dendermonde several times a week.

Veerle Heeren, the social welfare minister for the regional Flemish government, said an investigation would be launched to probe what security measures were in place at the centre.

With files from The Associated Press