PRAGUE (AP) - Police say a powerful explosion has damaged a building in the centre of the Czech capital, Prague, and they believe some people are buried in the rubble.

Police spokesman Tomas Hulan says it is not immediately clear what caused the blast in Divadelni Street on Monday morning.

The street is covered with rubble and has been sealed off by police.

Ms Jirina Ernestova, spokesman for the rescue service says rescuers expect some people are buried under the rubble.

Firefighters spokeswoman Pavlina Adamcova says at least 13 people have been injured.

Windows in buildings located hundreds of meters from the blast were shattered, including some in the nearby National Theatre.