President Mwai Kibaki has signed into law a media bill that journalists say will curtail press freedom.

The law gives the Kenyan authorities the power to raid media offices, tap phones and control broadcast content on grounds of national security.

Kenya's government has insisted it is committed to press freedom but the country's media have feared for its independence since a 2006 raid on a TV station and newspaper offices.

The Standard and its sister KTN TV station were accused of inciting ethnic hatred.

Under the new bill, it will be illegal for an individual or company to operate broadcast stations and press publications.

Several media organisations own both TV and radio stations as well as newspapers and publications.