The Czech central bank confirmed the attacks on its Facebook page, saying the assailants "targeted an external web server hosting the www.cnb.cz website".

The Prague Stock Exchange along with Ceska Sporitelna, Komercni Banka, CSOB and the local branch of Austria's Raiffeisenbank, were also victimised.

The brute force attack came two days after the nation's biggest media owners were hit by a cyber-broadside. Czech broadsheet DNES said the missiles were being fired from computers located in Russia.

In the US, meanwhile, the cyber fighters of al-Qassam pledged to renew their attacks on the nation's largest banks after a film poking fun at the prophet Mohammed resurfaced on YouTube. The Islamic hacktivist group stood down from its three-month long campaign in January after a trailer for the film disappeared from video-hosting Website.