Dutch Prime Minister Mark Rutte has sharply condemned a "cowardly" attack on a refugee shelter, vowing to deal harshly with a group of men who sprayed the building with fireworks and eggs.
Rutte visited the sports hall in the central city of Woerden on Saturday where some 150 refugees, including 51 children, are being temporarily housed, just hours after it was attacked late Friday by about 20 youths.
No one was hurt in the incident, but Dutch police were Sunday still questioning 11 men aged between 19 and 30 who were detained after the attack.
The men, all dressed in black and wearing balaclavas, had allegedly unsuccessfully tried to storm into the building.
"This cowardly action is totally unacceptable," Rutte said on his Facebook page, after visiting the group who he said had been very "shocked" by the incident.
It comes amid rising tensions in The Netherlands over the thousands of refugees due to be given shelter in the country under an EU scheme.
Over the next two years, it will take in more than 7,000 people as EU nations share out the migrants flooding into the continent, mainly from Syria and Iraq, in Europe's worst refugee crisis since World War II.
Last week, an angry crowd in the tiny village of Oranje tried to block the car of Deputy Justice Minister Klaas Dijkhoff after he tried to explain why the small hamlet was having to house some 1,200 refugees, twice the number initially planned.
A woman was injured and hospitalised after she threw herself against Dijkhoff's car.
Rutte, who on Friday had already called for calm over the refugee situation, vowed after his visit to Woerden that those behind the attack would be severely dealt with.
Some local mayors have reacted angrily at the government plans for temporarily housing refugees in their villages, saying they were being "overruled" by the ministers based in The Hague.
A poll published Sunday in the De Telegraf showed that the Freedom Party (PVV) of firebrand far-right Dutch lawmaker Geert Wilders appears to be shooting up the polls amid the refugee crisis.
His party won 15 seats in the last elections in 2012. But according to the daily De Telegraaf, if elections were held today his party could snatch as many as 35 seats in the 150-seat lower house.