At least 15 people have been confirmed killed and several others injured following a skirmish in Nigeria's northeastern town of Mambilla, local residents and the police said.Local police said the violence erupted on Thursday as a result of a misunderstanding between a farmer and a herder in Mambilla, home to Nigeria and west Africa's only highland tea plantations in the northern state of Taraba, Xinhua reported.Police spokesman David Misal said on Saturday that several homes were razed and cattle killed during the attack.Units of mobile policemen and soldiers have been deployed to the area to maintain law and order, Misal told reporters.