Russians scour wreckage for clues in plane crash that killed 71 Rescue operation gives way to recovery of remains and debris.

MOSCOW -- Hundreds of emergency workers are combing through a field in deep snow today for wreckage from a Russian passenger jet that crashed shortly after taking off from Moscow Sunday, killing all 71 aboard.

Saratov Airlines flight 703 was flying to the city of Orsk in central Russia but crashed minutes after leaving Moscow’s Domodedovo airport, plunging into the countryside about 40 miles from the city, authorities said.

Russian authorities have confirmed the plane's 65 passengers, including three children, as well as six crew members, died in the crash, which left debris across a field close to the village of Stepanovskoye. A day of mourning has been declared in Orenburg, the region where Orsk is located and where many of the passengers were from.

Russia’s Emergencies Ministry said today rescue operations at the site near Moscow had been called off and that the focus now was on recovering remains and debris from the crash as part of an investigation to determine what caused it. DNA analysis is being conducted to identify the remains of those killed.

Workers have found at least one of the plane’s flight recorders. Russia’s Investigative Committee, which handles serious crimes, said in a statement that the plane’s data recorder, which preserves information like speed, altitude and direction, had been located. The search for the plane’s cockpit recorder is continuing, the committee said.

The cause of the crash still remained unknown. Russian investigators have opened a criminal probe into whether negligence could have led to the crash but they have said they are still examining all possible versions, including weather conditions, technical failure or human error, among others.

Although terrorism has not yet been ruled out, police have suggested it is not being considered a likely cause.

The Investigative Committee, which is overseeing the crash investigation, said today the plane had been intact when it fell from the air and had not been on fire, suggesting there was no explosion on board. The plane exploded on impact with the ground, committee spokeswoman Svetlana Petrenko said in a video statement.

Investigators have been questioning staff at the airline, as well as ground staff and air traffic controllers who handled the flight. The Investigative Committee said the flight's crew made no distress call before the crash or indicated they were in difficulty.

After takeoff from Domodedovo, the plane made a slight left turn and reached an altitude of 6,400 feet and a speed of roughly 345 mph before suddenly plunging to the ground in less than a minute, according to FlightTrader24, a Swedish internet-based flight-tracking service.

There had been no technical complaints against the plane, a 7-year-old Antonov AN-148 regional jet that is a high-wing aircraft with twin turbo engines, Saratov Airlines spokeswoman Elena Voronova told ABC News.

“The crew was experienced, the plane was reliable,” she said.

Voronova identified the pilot as 51-year-old Valery I. Gubanov, who had 5,000 hours of flight experience, including 2,146 hours on the same kind of plane. She said the co-pilot, Sergey Gambarian, was also an experienced pilot.

The White House Sunday afternoon released a statement offering its sympathies for the crash. "The United States is deeply saddened by the tragic deaths of those on board Saratov Airlines Flight 703. We send our condolences to the families of those who lost their lives and to the people of Russia," the statement said.

No Americans are believed to have been aboard the flight, the U.S. State Department has said.

Russia’s aviation industry still suffers from a reputation for poor safety, inherited from the 1990s when it was plagued by crashes often caused by slack maintenance, aging equipment and weak government oversight. Recent years, though, have seen a marked improvement, with many carriers now equipped with modern fleets that are well-serviced.

But the past few years have still seen some major disasters.

In December 2016, a Tupolov TU-154 jet belonging to Russia’s military crashed into the Black Sea after taking off from Sochi for Syria, killing all 92 aboard, including members of a renowned army choir. In March 2015, 62 passengers on a FlyDubai 737 were killed when it crashed while landing in Rostov-on-Don.

In October 2015, 224 passengers and crew died when a bomb brought down a Russian charter flight operated by Metrojet while it was flying from the Egyptian resort Sharm el-Sheikh to Saint Petersburg. The Islamic State terrorist group claimed that attack.