A Russian airliner crash landed in the central Russian city of Samara on Saturday, killing seven people and injuring 23, emergency officials said.

It was unclear what caused the incident. Emergency Situations Ministry spokesman Viktor Beltsov described the accident as a "hard landing."

Another ministry representative, Irina Andrianova, said the plane was landing in heavy fog and grazed the runway with one of its wings. She said there was no fire after the crash.

The Tu-134 plane belonged to the Russian airline UTAir and had 57 people on board, including seven crew members, the company said in a statement. Two of the crew were among the injured, it said.

Andrianova said seven people were killed, 23 were hospitalized, six of them in serious condition, and the rest of the people on board were receiving psychological help.

Some Russian media, citing local emergency officials, reported that the plane landed on its fuselage after the landing gear failed to come down.

The plane had flown to Samara, about 550 miles southeast of Moscow, from Surgut, about 1,000 miles to the east.

Authorities were investigating the cause of the incident, transport officials and prosecutors said.

Tu-134s are widely used in the former Soviet Union. The last major crash of a Russian airliner was on Aug. 22, when a Tu-154 of Pulkovo Airlines crashed in Ukraine, killing all 170 people aboard.

In July, an Airbus-310 of S7 airlines went off the runway after landing in Irkutsk, smashed into adjacent buildings and caught fire, killing 123 of the 203 people aboard. In May, an Armenian Airbus-320 crashed into the Black Sea while trying to land in the southern Russian city of Sochi, killing all 113 people aboard.