A Venezuelan passenger plane slammed into a steep mountainside in the Andes, killing all 46 people on board, officials said Friday.

"By the way it crashed we can determine there are no survivors," said Gen. Ramon Vinas, head of the civil aviation authority.

Search teams reached the remote site by helicopter and had to lower themselves with ropes onto the "complicated" mountainous terrain, Vinas said.

"The impact was direct. The aircraft is practically pulverized," firefighter Sgt. Jhonny Paz told the Venezuelan television channel Globovision.

President Hugo Chavez declared that "Venezuela is in mourning" and called for a full investigation.

The French-made ATR 42-300 carrying 43 passengers and three crew members crashed Thursday at an altitude of 13,500 feet in an area known as Los Conejos plateau within the Sierra La Culata National Park, officials said.

The plane went down about 6 miles from the airport in the Andean city of Merida, where the Santa Barbara Airlines flight departed for Caracas, Vinas said.

Once the plane took off, the control tower received no further communication from the pilot, according to Jorge Alvarez, president of the small domestic carrier Santa Barbara.

Three helicopters were sent to the crash site, where winds and cloudy skies made it tricky to drop off emergency workers, said Gen. Antonio Rivero, the head of Venezuela's emergency management agency.

Extracting the aircraft's remains is likely to be "very difficult," Rivero said.

Relatives and friends of the victims gathered in tears, some of them embracing, at Simon Bolivar International Airport near Caracas.

"We join in the profound pain of all the relatives of our passengers and co-workers," the airline said in a statement. It pledged to cooperate fully with investigators.

Aircraft manufacturer ATR, based in Toulouse, France, said specialists from the company and the French Accident Bureau were leaving immediately to assist in a probe.

The weather was normal for Merida on Thursday, with some areas sunny and fog at higher elevations, said Lt. Luis Uzcategui of the Merida fire department.

"In that mountainous area there always tends to be more fog due to the altitude," Uzcategui said.

Among the dead were the mayor of a small town in Merida state, Alexander Quintero; his 11-year-old boy; and two young relatives of federal Public Safety Vice Minister Tarek El Aissami, state Gov. Florencio Porras said.