Most of those received only slight injuries from the blast in Na Prikope pedestrian precinct just off Wenceslas Square, one of the Czech capital's busiest streets, shortly after 12:30 pm (1030 GMT).

"Sixteen or 17 people were injured, all of them lightly. Most of them were hit by shrapnel or glass from the explosion," emergency services spokesman Marek Uhlir said on Czech state television.

According to Czech daily Pravo's online edition, one of those injured was a child.

Around 12 ambulances, together with police and fire fighters, were on the scene and more were being sent.