Russian investigators quickly ruled out a terror attack but will not speculate on possible reasons for the crash.

MOSCOW — Tramping through snowy fields outside Moscow, emergency workers found both flight data recorders from a crashed Russian airliner on Monday as they searched for debris and the remains of the 71 passengers and crew who died.

The An-148 twin-engine regional jet bound for Orsk in the southern Urals went down minutes after taking off from Moscow's Domodedovo airport Sunday afternoon. All 65 passengers and 6 crew on board were killed.

Russian investigators quickly ruled out a terror attack but will not speculate on possible reasons for the crash.

Still the crash has re-ignited questions about the An-148, since the model's safety record is spotty, with one previous crash and a series of major incidents in which pilots struggled to land safely. Saratov Airlines, which operated the plane, has grounded several other An-148s in its fleet pending the crash probe.

The Investigative Committee, Russia's premier state investigative agency, said the plane was intact and there had been no fire on board before it hit the ground. The plane's fuel tanks exploded on impact, scattering debris across 30 hectares (74 acres) in deep snow, according to the Emergency Ministry, which used drones to direct the search.

Deputy Prime Minister Arkady Dvorkovich told a Cabinet meeting that emergency teams have found both flight data and cockpit conversation recorders, which are crucial for determining the crash's cause.

Officials said the search for victims' remains at the crash site will take a week. The 65 passengers ranged in age from 5 to 79, according to a list posted by the Russian Emergencies Ministry. Most victims were from Orsk, where the authorities declared an official day of mourning on Monday.

President Vladimir Putin put off a planned trip to Sochi and stayed in Moscow to monitor the search operation and the crash probe.

Saratov Airlines said the plane had received proper maintenance and passed all the necessary checks before the flight. The plane was built in 2010 for a different airline that operated it for several years before putting it in storage. Saratov Airlines commissioned it last year.

The airline said the plane's captain had more than 5,000 hours of flying time, 2,800 of them in an An-148. The other pilot had 812 hours of experience, largely in that model.

Despite Saratov Airlines' move to ground its An-148s, another Russian operator of the plane, Angara, based in Irkutsk in eastern Siberia, said it will keep flying them. Russian government agencies that also operate the aircraft haven't grounded them either.