Millions of Colombians voted in a presidential election that is headed to a runoff between far-right candidate Abelardo de la Espriella and far-left Senator Iván Cepeda.

With most votes counted, de la Espriella led the first round with about 44% and Cepeda followed closely with about 41%, while other candidates trailed far behind.

The campaign has been dominated by concerns over violence, drug trafficking, and security, amid ongoing clashes involving armed groups and a high level of political instability.

De la Espriella has campaigned on a hardline security agenda including military strikes on traffickers and tougher prison policies, while Cepeda supports continued negotiations with armed groups and drug organizations, CBS News has reported.

The June 21 runoff will determine the country’s next president and could also influence future relations with the United States on counternarcotics and regional policy.