Belgian prosecutors said Friday they were investigating possible links between al Qaeda operatives and a diamond robbery at Brussels international airport two years ago, the Associated Press reported.

Jos Colpin, from the Belgian prosecutors office told the AP that Belgian authorities had carried out raids in several locations on Thursday, in Brussels and in suburbs around the capital city.

He said police briefly detained five people for questioning, but later released them without making any charges.

Colpin told the AP that they were looking for evidence of whether proceeds from a robbery on a Lufthansa aircraft which carried $162 million in diamonds and other goods went to radical Islamic groups linked to al Qaeda.

The unsolved diamond heist was carried out in October 2000, leading to an overhaul of airport security.

Belgian media reports said police were investigating possible links between the robbers and two Arab men-Nizar Trabelsi and Abdelkrim el Hadouti-arrested in September for alleged links to an Egyptian radical group that planned attacks in Europe, the AP reported.

JCK