Hundreds of people have joined a search for a Jewish teenager who has been missing from his home in London since last week.

Police said the disappearance of Asher Sekenofsky, 15, was a “high risk” incident, the Jewish Chronicle reported on Monday.

Seknofsky is 170 centimeters (5 ft. 7 in.) tall with dark curly hair, broad shoulders and a slim build and was wearing a green sweatshirt and black tracksuit pants. He was described as having a severe learning disability.

The Metropolitan police posted a notification on its website about the incident.

The Shomrim neighborhood watch group, a volunteer Jewish civilian patrol group, organized the search in coordination with local police. Shomrim posted notifications on its Twitter feed with a picture of Sekenofsky.

An operations room was also set up in a community center to direct the hunt.

Sekenofsky was last seen leaving his home in the Edgware district of north London at around 7:30 p.m. on Friday night.

A 24-hour hotline was set up on 0300 999 1234 and police appealed to the public for information on Sekenofsky’s whereabouts.