Witnesses said the action was taken after the channel reported that Mwai Kibaki, the president, had held secret talks with a political opponent.
Dozens of hooded officers carrying AK-47 assault rifles stormed into the headquarters of the Standard Group in the capital shortly after midnight and seized transmission quipment for the independent Kenya Television Network (KTN), they said.
They then went to the company's printing press and set light to thousands of copies of Thursday's edition of The Standard, Kenya's oldest newspaper, which had just been published.
Kitua Nzile, KTN news editor, said: "The media group has shut down its operations. The TV is off air after our equipment was seized and the newspaper is out of production because police have burnt printed copies."
During the operation, which followed the arrest of three journalists from the Standard group on Tuesday, police in civilian clothes briefly detained four employees of KTN and confiscated mobile telephones from overnight staff and harassed night guards, staff said.
Shinna Makena, a KTN video editor, speaking moments after they were released from custody, said: "They stormed the video production unit and ordered us to lie down. They then seized some transmission equipment before detaining us in Milimani and Central police stations."
Kalonzo Musyoka (R) has denied
reports of a secret meeting
An AFP journalist saw broken doors, shattered windows and dismantled security cameras in the Investment and Mortgage Building that houses the media company and several other private businesses.
The crackdown came after police confirmed detaining three Standard journalists over a report that appeared on Saturday alleging that Kibaki had held secret talks with Kalonzo Musyoka.
Musyoka is a former environment minister who was fired for campaigning against a draft constitution.
The draft, which would have given Kibaki more power in the first changes to the east African country's 1962 independence charter, was resoundingly defeated in a referendum last November, forcing Kibaki to reorganise his cabinet and fire renegade ministers.
Kibaki's press office and Kalonzo himself have denied that any such meeting took place and government spokesman Alfred Mutua has demanded that the Standard retract the article and apologise, which it has not yet done.
The arrests were condemned by local and international press watchdogs, who warned the government against clamping down on press freedom.
"We call on authorities to release our colleagues immediately and unconditionally, and ensure that the Kenyan press is free to report on political developments without such intimidation"
Committee to Protect Journalists
The New York-based Committee to Protect Journalists (CPJ) called the reporters' arrests an attempt to criminalise journalism.
In a statement, Ann Cooper, the CPJ chief, called "on authorities to release our colleagues immediately and unconditionally, and ensure that the Kenyan press is free to report on political developments without such intimidation".
Ezekiel Mutua, secretary general for the Kenya Union of Journalists (KUJ), told reporters late on Tuesday that "the same people who are trying to muzzle the media used to feed journalists with propaganda when they were in the opposition."
Kenya's high court is to hear on Thursday a suit filed by the paper's lawyer, Chacha Odera, seeking the immediate release of the three since they have not been charged with any offence.
Last month, police charged four weekly newspaper journalists for publishing a report claiming that Kibaki was senile and his government was torn apart by infighting.
Kibaki came to power in December 2002 when Daniel Arap Moi, the long-serving president whose regime was notorious for clamping down on press freedom, retired.