Four police officers have been arrested in Kenya after detectives raided a house where 37 Ethiopians were being held, about 16km (nine miles) from the capital, Nairobi.

The officers are suspected of aiding a human smuggling and trafficking operation.

The Ethiopians told Kenyan authorities that they were en route to South Africa in search of better lives, privately owned The Star newspaper reported.

A search is under way for the owner of the house and other members of the smuggling ring.

Kenya is a common transit route for Ethiopian migrants attempting to illegally enter South Africa, according to the UN migration agency IOM.

The agency says that the migrants, who are mostly men from Ethiopia's Oromia and SNNP regions, enter Kenya through the Moyale border point, before proceeding to Tanzania and eventually South Africa.