The white powder that brought an emergency response at the Grand Mosque in Brussels on Thursday turned out to be flour, a representative of the Brussels Fire Brigade and Emergency Medical Services told CNN.
A person in charge of mail at the mosque opened one envelope containing powder around 12:30 p.m. and, following safety procedures for anthrax, immediately contacted authorities, the official said. Four ambulances responded.
Seven people were in the room when the mail was opened and they were treated in a way that helped to ensure they were decontaminated from any potential harmful substance.
Ten envelopes with white powder were found, and analysts examined the substance, said Christian De Coninck, spokesman for Brussels police.
The news of the white powder at the mosque came amid heightened security in Brussels in the wake of the November 13 terror attacks in Paris that killed 130 people.
Also on Thursday, officials lowered Brussels’ terror alert to level 3 from the highest possible level, a 4, that had been in effect for days. The country is at level 3.
The Brussels Intercommunal Transport Company announced Thursday that all its subway lines will reopen Friday and bus lines will operate normally.
Police in Belgium have conducted several raids connected to the terror attacks. Investigators have focused particular attention on a Brussels suburb, Molenbeek, with a history of links to terrorism.
One of the suspected Paris attackers, Abdelhamid Abaaoud, was believed to have returned to the scene of the massacres in the French capital while the chaos was still unfolding, authorities have said. Investigators reportedly tracked his cell phone to the area.