Colombia slammed its neighbor Venezuela on Thursday for what it said was an "unacceptable" incursion by Venezuelan military forces on its territory, and sent troops to secure the area.
The move came just months after the two neighbors started to reopen their border following a security dispute.
Colombia\’s President Juan Manuel Santos said he had complained to his Venezuelan counterpart Nicolas Maduro that Venezuelan troops had set up a camp in the Colombian border region of Arauca.
"I told him that the situation is totally unacceptable for Colombia," Santos said in an address after a meeting with defense chiefs.
"He assured me that he had ordered the withdrawal of the troops from Colombian territory and we agreed to keep open a dialogue and diplomatic channels until the situation returns to normal."
Santos said Colombian "military personnel" had been sent to the area.
"I have instructed the armed forces to stay in the area and continue exercising full sovereignty over the territory."
The foreign ministry said in a statement earlier that it had "information from the Colombian armed forces about the installation of a Venezuelan military camp in the municipality of Arauquita," in Arauca.
It said the government had sent officials to the area to investigate and meet Venezuelan border authorities.
The countries in August started reopening border crossings after the frontier was closed a year earlier.
Venezuela had closed the border following an armed attack on a Venezuelan military patrol that left three soldiers wounded.
That attack was blamed on Colombian paramilitaries, remnants of Colombia\’s long civil war.
Colombian authorities also reported a further incident in January 2016 in which gunshots were exchanged in the area.
Arauquita is a strategic spot near the two countries\’ porous border, located on a road linking the Caribbean with the Pacific.