Britain's parliament was hit by a "sustained and determined" cyber attack on Saturday, targeting weak email passwords.

The cyberattack disabled some of the U.K. Parliament's communications, disrupting the ability of lawmakers to access their email, a House of Commons spokeswoman said.

In order to stop the attack from spreading, the government blocked members of Parliament from accessing their official email accounts from outside official buildings, she said. Computers within Parliament's buildings are working normally, according to her statement.

The House of Commons said it was working with the National Cyber Security Centre to defend parliament's network and was confident it had protected all accounts and systems.

The attack began Friday night, according to The Daily Telegraph newspaper.

The breach comes two days after The Times of London reported that passwords for MPs along with 8,000 other U.K. government and police officials were being offered for sale on Russian hacking sites.