Four people were slightly injured when a homemade explosive detonated at a bus stop in central Moscow.

Four people were slightly injured when a homemade explosive detonated at a bus stop in central Moscow, police said Tuesday.

The device went off Monday night on Pokrovka Street, a trendy area in central Moscow dotted with bars and restaurants.

"A hooliganism inquiry has been opened," Moscow police spokesman Maxim Kolosvetov told media outlets.

Preliminary information suggests the makeshift explosive was thrown either from a car or a nearby residential building and hurt "several" people, another Moscow police spokesman, Andrey Galiakberov, said.