Unidentified assailants have killed nine people and injured two others in the southern Nigerian state of Rivers.

"It was about 19:30 hours (1830 GMT) of yesterday (Friday). Some unknown armed men invaded Obrikom and Obor communities and went on a shooting spree," said Ahmad Muhammad, the state police spokesman, in a statement.

The gunmen also torched the house of Vincent Ogbagu, a local politician and a candidate in the upcoming parliamentary elections, he added.

According to Muhammad, the Nigerian security forces are still looking for the attackers in the oil-rich state.

The attacks came a week before the state gubernatorial and parliamentary elections, which are due to be held in around 30 Nigerian states.

Last week, Rivers witnessed clashes between protesters and security forces after Nigeria’s outgoing president, Goodluck Jonathan, was declared the winner of the presidential elections in the state.

The protesters attacked the electoral office in the state capital city of Port Harcourt, saying the elections in Rivers were rigged.

Following the clashes, the government imposed a curfew in an attempt to restore calm to the restive state. The curfew was lifted on Thursday.

According to Nigeria’s Independent National Electoral Commission (INEC), Jonathan lost the presidential polls to opposition leader, Mohammadu Buhari, who managed to secure 53.95 percent of the total valid ballots.

Nigeria has been grappling with the rising threat of Boko Haram Takfiri terrorist group since 2009.

Boko Haram, whose name means “Western education is forbidden,” controls parts of northeastern Nigeria and says its goal is to overthrow the Nigerian government.

It has claimed responsibility for a number of deadly shooting attacks and bombings in various parts of Nigeria, which have left over 13,000 people dead and 1.5 million displaced.

Boko Haram recently declared allegiance to the ISIL Takfiri group, which is perpetrating heinous crimes against humanity in areas under its control in Iraq, Syria and Libya.

FNR/HMV/SS