Thousands of demonstrators have been marching through Kenya's capital, angry at a police raid on a media group.
Protester want John Michuki to go
The Nairobi protesters waved placards demanding that Internal Security Minister John Michuki "must go".
Last week, hooded policemen seized equipment, halted TV broadcasts and burned thousands of newspapers belonging to the Standard media group.
The operation has been described as the biggest media crackdown seen in Kenya since independence.
Thousands of others are reported to be protesting in the cities of Mombasa, Nakuru and Kisumu.
The raid followed a story published by the media group that said the president had secretly met a leading opponent.
Some protesters held placards that read: "Mr President, Stop Sponsoring State Terrorism."
A protester told AP news agency that a free press in Kenya was vital.
"The assault on the Standard newspaper group was outrageous and shouldn't happen in a democracy, and those responsible should go, without negotiation," said Rhoda Atieno.
The demonstration was organised by a coalition of opposition parties known as the Orange Democratic Movement.
The internal security minister said the raids, which have provoked national and international condemnation, were designed to protect state security.
"If you rattle a snake, you must be prepared to be bitten by it," John Michuki said.
Demonstrators also called for Communications Minister Mutahi Kagwe to step down.
During the raid, masked and armed police seized tapes, destroyed equipment and burned thousands of copies of the Standard newspaper at the press where it is printed.
Thousands marched through Nairobi's streets
A similar raid was carried out at the Kenya Television News (KTN) station.
The Standard - Kenya's oldest newspaper - has been critical of President Kibaki's handling of recent corruption scandals. The government has repeatedly accused the newspaper of fabricating stories.
The paper has threatened to sue the government over the raids.
Three Standard journalists, arrested before the raids over a story about President Kibaki, have been charged with publishing alarming statements and released on bail.