(ANSA) - BERLIN, 04 LUG - Much of the Czech Republic was paralyzed today by a power blackout, the CTK news agency reports. In the capital, Prague, the metro and trams came to a halt. Firefighters were continuously on duty to free people trapped in elevators. The situation is gradually returning to normal. For now, the reasons for the blackout remain unclear; the Interior Ministry has convened a crisis unit. (ANSA).