The hacktivist collective Anonymous says that it has attacked government websites in retaliation for the UK's handling of the Julian Assange case.
It claimed responsibility on Twitter for the denial-of-service attacks. Websites affected include the Ministry of Justice and the Home Office.
The latest attacks were launched on Monday and most of the affected websites appeared to be operating normally on Tuesday evening.
A spokeswoman for the Ministry of Justice website said it "had been experiencing some disruption" and that "The Ministry of Justice website was the subject of an online attack."
The Ministry of Justice website is a public information site, and held no sensitive or confidential data.
"Measures put in place to keep the website running mean that some visitors may be unable to access the site intermittently," said the spokeswoman.