By Tife Owolabi

YENAGOA, Nigeria (Reuters) - Gunmen in Nigeria killed five aides including security personnel during an attack on the convoy of a Nigerian senator in southeastern Anambra state on Sunday evening, the senator's spokesman said on Monday.

Senator Ifeanyi Ubah's convoy was attacked in Enugwu-Ukwu, a community in the Njikoka local government area of Anambra but he escaped without injuries because he was travelling in a bullet-proof vehicle, spokesman Kameh Ogbonna told Reuters.

Ogbonna said he was in the same car with Ubah at the time of the attack, which he described as an assassination attempt.

Police said they were investigating the incident and would give an update later.

Unknown gunmen have been responsible for a series of attacks on politicians, security forces and government targets in the southeast, where separatists are agitating for secession.

The government accuses outlawed separatist group Indigenous People of Biafra (IPOB) for the attacks and other criminal activities in the region. IPOB denies the charge and says it seeks non-violent means to achieve its aims.

(Reporting by Tife Owolabi; writing by MacDonald Dzirutwe; editing by Jonathan Oatis)