A police spokeswoman said the men had moved to work on a busy city centre street which they found more lucrative.

President Mwai Kibaki has pledged to vigorously fight corruption in public life since taking office last December.

Half the most senior judges have been suspended but the BBC's Gray Phombeah in Nairobi says that corruption has not reduced but it is now taking new forms.

He says that while police officers used to openly ask for money from the drivers of "matatu" minibus taxis, they now send intermediaries to collect the bribes on their behalf.

Video nasty

Police spokeswoman Naomi Wayama told Kenyan radio that after complaints had reached them, they videotaped the police officers in action early in September.

She said eight officers were dismissed and other disciplinary measures were taken against another six.

"In spite of the policy of zero tolerance to corruption... we in the Kenya police have noted, with regrets, that bribe taking and other forms of corruption are creeping back to some of our officers," she told KBC radio.