The source of the attack was not immediately clear.

The chamber on Wednesday passed a resolution condemning the Russian authorities as a terrorist regime.

"I do not know whether this is the result of yesterday's resolution or just a coincidence, but a strong hacking attack on our servers has been going on for about 40 minutes," speaker Tomasz Grodzki told the chamber.

At 1010 GMT, the website was working again in Poland.

(Reporting by Alan Charlish)