Updated

A grenade exploded Wednesday at an outdoor bus depot in Guyana's capital, decapitating one person and wounding at least 19 others, according to police and hospital officials.

Georgetown Police Commander George Vyphuis said detectives are trying to determine who set off the deadly blast in the depot near the bustling Stabroek Market. Police have detained a shopkeeper at a roadside beverage stand for questioning.

"Right now the area is still cordoned off as we try to figure out what exactly happened," Vyphuis said.

Police said the casualty was a handyman whose head was blown off by shrapnel from the grenade.

Local shopkeepers said the dead man was a deportee released from a U.S. prison years ago. The man was often hired to keep vending stands tidy but local business people told investigators they did not know his name or where he lived.

Authorities declined to speculate on a motive or say if the grenade may have exploded accidentally.

Officials at Georgetown Hospital said 19 hurt people, including a 4-year-old boy and his 76-year-old grandmother, were being treated for shrapnel wounds. The extent of their injuries was not immediately disclosed.

Witness Roland Singh told reporters that the late morning blast left him temporarily deafened and he saw some of the wounded screaming from their injuries.

The grenade explosion has rattled the capital of Guyana, a nation on South America's northeastern shoulder that is more aligned with the Caribbean.