COLOMBIAN voters have turned out to elect a new Congress and to select candidates from three major coalitions in a primary-style contest ahead of a presidential election in May.

Sunday’s election was held amid a nationwide high alert for political violence.

Preliminary results showed that President Gustavo Petro’s Historic Pact (HP), which includes the Communist Party, and the main opposition Democratic Centre (DC) had received the most votes in the Senate election. HP looks set to secure four more seats.

In the House of Representatives, the DC received the most votes, followed by parties such as the Liberals and the Conservatives. The HP appeared to be heading for fifth place.

Hours after the polls opened, Defence Minister Pedro Sanchez said a group of at least 2,400 people “allegedly heading to vote” had been detected trying to enter Colombia from Venezuela at an illegal border crossing.

The minister, who posted images on social media showing people queuing up to cross a river to the other side, where several buses were parked. 

President Petro described the incident as “large-scale fraud” and an “avalanche of illegal voting.” 

“Sixty buses have been detained and the company responsible for bringing massive numbers of voters from across the border must be investigated immediately,” he said.