Colombia is heading into a tense presidential runoff after one of its most violent election campaigns in decades, with security forces on alert following the killings of political figures.

Voters face "radically differing options" on security, the journalist Richard McColl told DW, especially in areas controlled by armed groups. The race pits left-wing senator Ivan Cepeda against right-wing lawyer Abelardo de la Espriella, whose lives have been shaped in very different ways by the country's decades of conflict.

Cepeda, whose father was killed by paramilitaries, has built a career defending human rights and victims.

De la Espriella, who has based his platform on a hard-line clampdown, "has represented almost every single one of the top members of these right-wing paramilitary groups," McColl said.

Security is a central issue. About 27,000 fighters remain active across Colombia.

McColl said the country remained "very violent" and fears of intimidation and coercion loom over the vote.