A witness says militants from opposing political parties killed two soldiers and four police officers in shootouts after the governor of Nigeria's oil-rich Bayelsa state was declared the winner of elections there.

Saturday's election was a rerun because of violence, ballot box theft and fraud that marred Dec. 5 balloting. Incumbent Governor Dickson Seriake of the People's Democratic Party easily won the vote in the southern state that is home to former President Goodluck Jonathan, who was defeated in March elections by former military dictator Muhammadu Buhari.

Philip Okolo of the Society for Peace Studies and Practice said hours later that militants were involved in a shootout and that he saw several people killed, including two soldiers and four police officers.