Policemen and firefighters inspect the scene of an explosion in downtown Prague, Czech Republic, Monday, April 29, 2013. Police said a powerful explosion has damaged a building in the center of the Czech capital, and they believe some people are buried in the rubble. (AP Photo/Petr David Josek)

Photo by: Petr David Josek

Policemen and firefighters inspect the scene of an explosion in downtown Prague, Czech Republic, Monday, April 29, 2013. Police said a powerful explosion has damaged a building in the center of the Czech capital, and they believe some people are buried in the rubble. (AP Photo/Petr David Josek)