Belgian police held a Palestinian minister on board his plane on Friday after Dutch authorities withdrew his visa to attend a conference in the Netherlands, Dutch authorities and conference organizers said.

Youth and Sports Minister Bassem Naim, a Hamas member, arrived in Brussels on a flight from Egypt after being granted a visa by Dutch authorities in Tel Aviv. But he was prevented from disembarking by 10 Belgian police, said Majed al-Zeer, director of the London-based Palestinian Return Center and one of the organizers of Saturday's conference on Palestinian refugees.

"What happened on the flight was the humiliation of the Palestinian people," Al-Zeer told The Associated Press. "He was not even allowed to go to the toilet."

Dutch Foreign Ministry spokesman Ahmed Dadou said Naim had been granted a visa but that it was withdrawn on Thursday after checks revealed his Hamas affiliation. Dadou said Dutch authorities contacted Naim and made it clear he would not pass through Dutch immigration control.

"We told him his visa was canceled from that moment ... and for that reason there was no way he would be able to get into the Netherlands by legal means," Dadou said.

Naim tried to board an Amsterdam-bound flight Thursday night but was turned away, Dadou said. He then managed to get on an Egyptian plane from Cairo to Brussels on Friday. "Now he will be sent back with the first flight available," Dadou said.

Saturday's conference in the Dutch city of Rotterdam, which is an hour by road or rail from Brussels, is expected to attract Palestinians from around Europe to discuss the plight of Palestinian refugees.

Palestinian Prime Minister Ismail Haniyeh was invited to attend but Dutch authorities said they would not grant him a visa. Haniyeh is expected to address the conference via a videolink, organizers say.

Naim is a senior Hamas figure who at one stage was touted as a possible prime minister.