Abuja, April 21 (IANS) At least 107 suspects involved in post-election violence in northern Nigeria have been arrested, an official said.

Commissioner of Police of Katsina state, Ibrahim Mohammed, said 15 churches were burnt down by protesters and properties belonging to supporters of the ruling party as well as non-indigenous people were affected.

A total of 42 inmates escaped from a prison in Funtua when the protesters stormed the place and scared away the prison officers, according to Xinhua.

Mohammed said four people were burnt to death when their homes were set ablaze by protesters.

Groups of youth unhappy with the outcome of the country's presidential election - held April 16 - stormed the streets of Katsina state, burning homes belonging to supporters of the ruling Peoples Democratic Party.

They also burnt secretariats belonging to the ruling party, razed shops and houses where corps members stayed, as well as burned goods in shops.

Retired army general Muhammadu Buhari had contested against President Goodluck Jonathan for the presidential seat, but the election results favoured the incumbent.