The European Union has expressed concern over Sri Lanka's move to block certain anti-government websites, days after the US demanded that Colombo respect freedom of expression.

"The EU considers that freedom of press forms is an integral part of any democratic system. The EU therefore believes that the media should be allowed to operate independently," an official statement by EU heads of diplomatic missions here, said.

The Sri Lankan ministry of media had on Saturday ordered news websites publishing reports about Sri Lanka to obtain accreditation from the information department.

Over the last two days several websites have been blocked including Lankawaynews.com, which is said to be Opposition UNP's official website.

The Ministry of Mass Media and Information had said it was "receiving many complaints from various individuals who have been subjected to defamation and character assassination by certain reports published in several websites".

The President, ministers, and senior public officials have come under attacks and deliberate character assassination campaigns in such reports, it added.

Sri Lanka has already blocked anti-government websites like Lankanewsweb, Lankaenews and TamilNet.

The US embassy had this week said that freedom of expression, including unfettered access to Internet news websites, was a basic right which must be respected by Sri Lankan authorities.