Russia's chief prosecutor has briefed President Vladimir Putin about Tuesday's almost simultaneous crashes of two passenger planes that killed 89 people.
Chief Prosecutor Vladimir Ustinov said authorities are considering terrorism, technical problems or human error as possible causes of the crashes.
The talks were held in Moscow Wednesday following Mr. Putin's return to the Russian capital after cutting short a vacation in the Black Sea city of Sochi, the destination of one of the planes.
The two aircraft took off from Moscow's Domodedovo airport within an hour of each other. One activated a distress signal before going down.
Residents reported hearing an explosion before one jetliner crashed in the Tula region, about 180 kilometers south of Moscow.
Wreckage from the other plane was spread over several kilometers near the southern city of Rostov-on-Don.
Russia has declared Thursday a day of mourning for the victims.
Information for this report is provided by AP and AFP.