Flames engulfed a shelter for homeless people in north-western Poland.

These pictures show the blaze billowing from the three-storey building's windows, reaching far into the sky.

At least 21 people were killed.

Another 20 were injured in the fire, in the town of Kamieniec Pomorski on the border with Germany.

Many of them were sustained as residents jumped from upper floors of the building to escape the overnight blaze.

Some 77 people were registered at the hostel, but the exact number there at the time is unclear. Residents were waiting for local authorities to provide them with housing.

Prime Minister Donald Tusk visited the scene and promised government help for survivors.

President Lech Kaczynski declared three days of national morning.

Emergency teams began sifting through the wreckage of the building, expecting to find more victims.

The cause of the blaze is not yet known.

But survivors said this was not the first fire in the hostel.