Eleven illegal aliens awaiting deportation from the Netherlands have been killed in a fire at a detention center on the grounds of Amsterdam's Schiphol airport. Dutch authorities have, so far, not released the names and nationalities of the dead.

The blaze broke out at midnight, Amsterdam time, and was not extinguished until daybreak. The cause of the fire is still unknown, but authorities say they do not rule out arson.

Fifteen people, including firefighters and airport police, were injured in the blaze.

The detention center, housing about 350 people, is actually a series of prefabricated containers where drug smugglers, illegal immigrants and asylum seekers whose appeals have been exhausted are held. Dutch radio reported that 43 people were in the area that caught fire.

Surviving detainees have now been moved to other detention centers, and one of them told Dutch radio that guards at the facility did not take reports of the fire seriously and refused to open the cells.

Dutch authorities say each cell door had to be opened manually and that there was no mechanism to open them all at once.

Michel Bezuijen, an official of the district where the airport is located, told reporters that an inquiry will be set up into the fire.

"We will appoint a third party to carry out an independent investigation into what happened, not just how the fire started, but also [whether] the safety measures were adequate and so on," he said.

After a center-right government came to power in the Netherlands three years ago on a tough anti-immigration platform, the country, once one of Europe's most tolerant, began deporting thousands of failed asylum seekers.

Human rights groups have criticized the policy, saying some of those people have been deported to countries where they could face persecution or abuse.

Schiphol, the fourth busiest airport in Europe, is also regarded as a hub for drug smuggling. Dutch police say that, last year, they arrested more than 3,000 drug traffickers at the airport, mainly from the Netherlands Antilles and South America. A police spokesman says about half of the detainees at the burned holding center were drug smugglers.