Investigators began retrieving the bodies of 46 people who died in a plane crash in the Venezuelan Andes, as victims' relatives mourned their loved ones during a Sunday Mass.

Forensic experts brought six body bags containing victims' remains down from the crash site, located on a steep slope 13,500 feet above sea level, Venezuelan Civil Aviation director Gen. Ramon Vinas said.

The twin-engine ATR42-300 crashed and burst into flames Thursday in the Sierra La Culata National Park, shortly after taking off from the Andean city of Merida on a flight to Caracas. Three crew members and 43 passengers were aboard.

It could take weeks to recover and identify all of the bodies through DNA testing, said Noel Marquez, director of Merida's emergency management agency.

Searchers were "making every effort to retrieve the remains of the victims," President Hugo Chavez said Sunday on his weekly television program.

"We pray for 46 souls ... all of those who were affected by this tragedy," Archbishop Baltazar Porras told tearful relatives and friends of the victims, who attended Mass Sunday at a Merida church.

Searchers on Saturday recovered the plane's two "black boxes" — cockpit voice and data recorders that could indicate what went wrong. Investigators say the pilot for Caracas-based Santa Barbara airline made no distress call before the crash.

The victims were mostly Venezuelan, but also included five Colombians and a U.S. citizen, Vivian Guarch, 53, who worked for a Miami branch of Stanford Bank, officials said.