The demonstrators from the All Progressives Congress (APC) converged on the local offices of the Independent National Electoral Commission (INEC) in the state capital, Port Harcourt.
Military fighter jets and ground troops also pounded Boko Haram fighters in the northeastern state of Bauchi after a series of attacks on polling stations on Saturday and Sunday.
The Independent National Electoral Commission (INEC) in Kano on Sunday announced the cancellation of election results of two polling units in two local government areas of the state
He said that the directive was given to the service late on Saturday as the country needed to resume activities within and across its land borders which had been closed since Wednesday.
The News Agency of Nigeria (NAN) reports that the voters kept vigil till 2.45 a.m. on Sunday to monitor counting of the ballots and hear the result of the polls at the unit.