Passengers' relatives fear the worst
The search is set to resume on Tuesday morning, but hopes are fading for the 92 passengers and crew who were on board the TAME airline's flight 120.
Civil and military aircraft from Ecuador and Colombia had tried to fly over the area where the plane lost contact with air traffic controllers.
But a spokesman for Colombia's Civil Aviation Department said weather conditions disrupted their efforts.
"There is a lot of fog in the zone, which is complicating the search," the spokesman said.
The TAME state airline Boeing 727-100 took off from Ecuador's capital Quito on Monday morning on an internal flight bound for the northern border town of Tulcan, 135 kilometres (85 miles) away.
Authorities said control towers at both airports lost contact with the plane after it requested permission to land at Tulcan.
Colombian rescue services say they have pinpointed the crash site between Tulcan and the Colombian town of Ipiales.
The plane was carrying 83 passengers, seven crew and two mechanics.
The plane was scheduled to fly on to the Colombian town of Cali, and many of the passengers are reported to be Colombian nationals.
Volcano
A farmer in the area, which is mountainous and remote, told Colombian Radio that he feared the plane had crashed into El Cumbal, a 4,700-metre high active volcano.
The farmer, Arturo Cruz, said he saw the plane then heard a loud explosion.
The BBC's Jeremy McDermott, reporting from the Colombian capital Bogota, says rescue services on both sides of the border have been mobilised, but the area in which the plane came down is thick jungle and almost impossible to reach.
Earlier this month, a plane belonging to the Ecuadorean state oil company Petroecuador crashed in Colombia, killing all 26 people on board.
It was six days later before searchers found the wreckage of the twin-engine propeller plane on the side of a hill a few kilometres across the border.
Another TAME Boeing 727 crashed in Colombia in 1998, smashing into a mountain near the capital Bogota and killing all 43 passengers and 10 crew on board.