Police are appealing to members of the public to help trace 79-year-old Abdellatif Yacoubi, who disappeared after leaving his home in Jette on Wednesday evening.
He is 1.75 metres tall with a slim build, brown eyes, a bald head with short grey hair on the sides and a goatee.
When he disappeared, he was wearing a green and brown T-shirt, a black Adidas tracksuit jacket with white stripes, blue jeans and grey trainers.
Yacoubi was last seen at around 21:00 after leaving his home on Avenue de l'Exposition. He has since been spotted at the Arts-Loi and Brussels-Midi metro stations but has not been seen since.
Police said Yacoubi may appear confused and disoriented.
Anyone with information about Abdellatif Yacoubi's whereabouts is urged to contact investigators via the Belgian police's online witness appeal form or by calling the free number 0800 30 300. Witnesses calling from abroad can contact police on +32 2 554 44 88.
