Despite a three-day intensive search, there has still been no sign of the Colombian plane carrying 15 soldiers and three civilians which has been missing since Monday.
"Lamentably, an accident occurred," the commander of Colombia's armed forces, General Freddy Padilla said on Wednesday.
"The aircraft sent an alarm in a humid, mountainous area, and we have had no success in the rescue," he said.
Colombia's armed forces said on Monday that National Air Company flight number HK 4055, carrying Number 10 Mobile Brigade soldiers, has been missing since Monday in the central Colombian province Meta.
Jorge Diaz, Commander of Colombia's Civil Defense Organization, said that three Colombian Air Force aircraft, military units and land rescue units are doing all they can to reach the area where the accident is thought to have taken place.
"There is an emergency signal and we are searching alongside Red Cross staff and mountain rescue-trained volunteers. They have material for five days' worth of searching," he said.
Rescuers said that a resident had seen the plane fly over his home and then disappear.
"A man has said he saw an aircraft and then could no longer hear it, shortly after it flew over his home," said Diaz's colleague Manuel Mantilla.
"This is a hypothesis that we are trying to verify. It seems there was no bad weather in the upper sky, but there were a lot of clouds lower down," he said.
The soldiers had been traveling to the Meta town of La Uribe for a two-month training session. Their families have now gone to the region's military garrisons to wait for news.
(Xinhua News Agency October 11, 2007)