The Boko Haram fighters were reported to have crossed Nigeria’s border into Cameroon earlier this week after attacking a military base and police station in Borno, north east Nigeria.
The attack was said to have apparently sent some 480 Nigerian troops retreating across the frontier.
“Cameroon soldiers have killed 27 Boko Haram elements during an attack in a locality near Fotokol in the far-north,” state radio/CRTV said.
It added that the deaths occurred on Monday and Tuesday but there was no word on any Cameroonian casualties.
A Cameroonian soldier in the region said the militants had been pushed back into Nigeria, with calm returning to the area on Wednesday.
In recent weeks, Boko Haram, which is seeking to carve out a de facto Islamic state in northern Nigeria, has stepped up attacks in Cameroon.
It has forced the central African country to increase deployments along its jungle border.
But Cameroon has not always been successful in fending off Boko Haram raids.
Last month, President Paul Biya dismissed two senior army officers following attacks in which at least seven people were killed and the wife of the vice prime minister was kidnapped.