Four buses that had been dispatched to Mombasa to evacuate residents of Embu County were intercepted by police at Masinga in Machakos County and ordered back to the coastal city.
Lower Yatta Police Commander Charles Chacha said the buses were intercepted at a check point on the Kanyonyo-Embu road.
Mr Chacha said more than 100 passengers were being ferried from Mombasa, which has registered about 19 Covid-19 cases, to their rural homes in Embu and Meru that have, so far, recorded no cases of the disease.
Movement in and out of the Nairobi Metropolitan Area, Kilifi, Kwale and Mombasa counties has been stopped to contain the spread of the coronavirus.
"We are keen on barring the movement of people from restricted areas. We ordered the buses to be driven back to Mombasa. A team will escort them to the boundary with Makueni where they will be handed to another team. This will continue until they are in Mombasa," said Chacha.
On Wednesday, Embu County Commissioner Abdullahi Galgalo said they were on high alert after being tipped off by the public that four buses had been dispatched to Mombasa to bring residents back home.
Mr Galgalo warned Kenyans against flouting measures issued by the government to contain the spread of Covid-19.
Meanwhile, the Nakuru County security committee has said it will close all illegal routes that people are using to leave Nairobi, which is under a 21-day partial lockdown.
Nakuru County Commissioner Erastus Mbui said travellers were using 'panya' routes through Kiambu to Naivasha before proceeding with their journey to western Kenya.
He said police had forced several vehicles to turn back after they were found ferrying residents from the capital city.
"We are warning the drivers and their passengers that they will face the full force of the law."