Ecuador will hold a runoff in October to choose the country's next president.

None of the eight candidates won outright in the first round of the election on Sunday. The runoff will be held between the two top contenders, leftist Luisa Gonzalez and rightist Daniel Noboa.

Voting took place amid tight security after candidate Fernando Villavicencio was gunned down in the capital Quito on August 9. He had pledged to fight corruption and organized crime. A nationwide state of emergency was declared after his assassination.

Crime involving drug cartels has become a serious social problem in Ecuador. Security measures are expected to be a major issue in the runoff.