Rescue workers pulled more bodies from the ruins of a collapsed supermarket in the Latvian capital, Riga, on Friday (November 22) taking the death toll to 21 with others feared buried in the rubble.

The store, estimated at around 500 square meters in size, was bathed in spotlights as diggers and rescue workers cleared away the wreckage.

It was not clear what caused the collapse, but Interior Minister Rihards Kozlovskis told Latvian TV by telephone: "It is clear that there has been a problem with fulfilment of construction requirements."

Around 25 people waited near the wreckage for news of their relatives. The number of those trapped was so far unknown.

Rescue workers were called to the store, which according to local media had been awarded an architecture prize when it was completed in 2011, late on Thursday.

Three fire-fighters were killed and several other rescue workers were injured in a second collapse because of the building's weakened structure.

Rescue workers were stopping work periodically to listen for survivors and for the sounds of mobile phones in the wreckage, Latvian TV said.

Early on Friday, cranes were working to lift and take off concrete blocks which are hampering rescue efforts, state fire and rescue service chief Oskars Abolins told Latvian TV.

Local media said workers had been building a roof garden on the store.

Presented by Adam Justice