Shots were fired and four soldiers were killed at a naval base on the Colombian Caribbean island of San Andrés.
According to initial information, a marine allegedly shot dead three comrades and injured an army soldier on Saturday morning (local time), as the navy of the South American country announced.
Then the perpetrator apparently killed himself.
The background to the act initially remained unclear.
The incident was deeply painful, wrote President Iván Duque on Twitter.
He promised a quick clarification.