Senator Miguel Uribe (Photo:The City Paper Bogota)

This is a direct threat to democracy, he said, adding that those responsible for the attack must face justice.

Spain conveys its best wishes for a speedy recovery to the candidate and expressed solidarity with his family and friends, as well as the Colombian people, the Spanish Foreign Ministry said in a statement.

Colombian senator Miguel Uribe was speaking to supporters in the capital when a gunman shot him twice in the head and once in the knee.

A security guard managed to detain the attacker, an individual believed to be 15 years old. Colombian authorities are investigating to find out if there were other perpetrators.