BRUSSELS (Reuters) - Belgian police have arrested a man believed to be part of a paedophile pornography network involving the Netherlands, Belgium and Portugal, the justice ministry said on Wednesday. "One man was arrested last week. Child pornography videos were found at his home in Belgium," a spokeswoman said. "It is in connection with a paedophile pornography affair in Portugal." She gave no further details. The arrest follows a campaign launched by Nelly Maes, a deputy in the Flanders regional government, who said earlier this month she had seen a video dating from 1992 of two elderly men abusing underage boys on the island of Madeira. One of the men had a Dutch accent and the other a Belgian accent, she said, adding that the boys were aged between eight and 13 years old and visibly resisting the abuse. Maes also said she knew of another video by the same men of a boy, reported missing in Germany. On Tuesday the parents of Manuel Schadwald, who disappeared in Berlin four years ago at the age of 12, visited Belgian Justice Minister Stefaan De Clerck to ask him to take action. They said they had recognised their son in a clip shown on Dutch television of a pornographic video made by a Dutchman and a Belgian man. De Clerck said earlier this month, in response to Maes' campaign, that he was powerless to act as the offences had been committed before Belgium introduced a law enabling it to prosecute its nationals who committed sex crimes abroad. Maes said that the paedophile pornography ring included a Portuguese man who acted as interpreter. Portuguese police arrested a local man two weeks ago on suspicion of being involved in a paedophile ring linked to Belgium. Portuguese television said at the time Agostinho Sousa had been identified from explicit videos. Sousa denied being part of a paedophile network. The affair follows the discovery in Belgium in August last year of the buried bodies of four young girls who had been abducted, sexually abused and murdered in a case that sent a wave of revulsion through the country. Convicted child rapist Marc Dutroux has been charged with all four murders. He denies committing them, blaming instead an accomplice who he admits killing and his second wife Michelle Martin. The body of a fifth young girl was discovered in March this year, stuffed into a steel trunk in the basement of a Brussels garage. Convicted child molester Patrick Derochette has been charged with rape leading to the death of a minor.