Soldiers worked with residents to rescue people trapped in the rubble and set up tents and mobile kitchens for those made homeless, Anatolian news agency said on Friday.
Istanbul's Kandilli Observatory said the quake measured 5.1 on the Richter scale.
An official at the local governor's office said the village of Yigincal, with about 100 houses, suffered severe damage in the quake, which struck three villages in Dogubayazit district near the Iranian border at 01:30 (22:30 GMT).
Residents wailed as bodies were pulled from the rubble in Yigincal, where all the 18 dead were found, Anatolian said. It said there had already been several aftershocks.
"Work is continuing on clearing away the rubble. There is also damage in other villages, but there are only slight injuries there," the official said.
"Work is continuing
on clearing away the rubble. There is also damage in other villages, but there are only
slight injuries there"
Agri governorate official
The first television pictures from the scene showed emergency workers carrying the injured into an ambulance while locals looked on amid devastated one-storey houses.
The remote Dogubayazit area is a destination for adventurous travellers who come to visit Mount Ararat and palace ruins on a hill near the main district town.
The Red Crescent aid organisation said it had sent 500 tents and 500 blankets to the area along with two mobile kitchens, Anatolian reported.
Agri Governor Huseyin Yavuzdemir told CNN Turk television he did not think the death toll would rise, because it was summer. Many north-easterners move to homes in the mountains in summer months to escape the heat.
"The search and rescue is finished ... . There is no one in the rubble. These are not buildings that can withstand earthquakes, they are made of earth and stone. Some of the houses are made of concrete and those are fine," Yavuzdemir said.
The weather in the area is mild and locals spent the night outside, he said.
Earthquakes are common in Turkey, which is criss-crossed by geological fault lines.
Nine people were killed and dozens injured when a quake of the same magnitude hit Erzurum province in eastern Turkey in March.
A massive quake in August 1999 killed some 18,000 people in an industrial area of north-western Turkey.