COLOMBO, Sri Lanka — Sri Lankan police arrested nine journalists and seized computers and documents from the office of an independent news website Friday, said a media rights group in one of the world’s most dangerous countries for journalists.

Police said they had a court warrant to act against Srilankamirror.com but they have not explained the reasons for the arrests, said Gnanasiri Kottigoda, the president of the Sri Lanka Working Journalists Association, a local media rights group.

The site was among five blocked by the government last year in a move criticized internationally as a violation of media freedom.

A court settlement restored access to Srilankamirror.com a month later.

Friday’s police action clearly shows that ‘‘the government has not stopped its campaign to harass and intimidate the independent media institutions and journalists in Sri Lanka,’’ Kottigoda said.

More than a dozen police officers surrounded the office.

ASSOCIATED PRESS