Election observers say violence, intimidation and voter apathy led to low turnout in Nigeria's elections for governors of 29 states over the weekend.

Nigeria's electoral commission suspended all election activities in two southern states, Rivers and Akwa Ibom, due to the chaos.

European Union observers on Monday noted "systematic failings, including a lack of transparency" but said it was an improvement over the presidential election on Feb. 23.

Its statement said observers were denied access to vote compilation centers in Rivers state.

The International Republican Institute and the National Democratic Institute joint observer mission in a separate statement said a heavy military presence undermined the integrity of the vote in some parts of Africa's most populous nation.

Nigeria's military has blamed any crimes on people impersonating soldiers.