SALONIKA, Greece (Reuters) - Greek rescue teams clawed through rugged mountains covered with snow and low cloud on Thursday in the search for a missing Ukrainian airliner with at least 70 people aboard. Officials said there was growing concern that the plane would not be found before nightfall. The Russian-built Yakovlev-42 plane, flown by the Ukrainian-Israeli Aerosweet Airlines, disappeared from radar screens late on Wednesday evening as it prepared to land in Salonika airport after a flight from Kiev via Odessa. Authorities said they were now focusing their search on a mountainous region some 50 km (30 miles) southwest of Salonika, north of the celebrated Mount Olympus of ancient Greek legend. More than 1,000 military personnel were involved in the search, aided by locals including farmers on tractors. Villagers in one remote area fired rifles in the air hoping to attract attention from possible survivors. The airline said the plane was carrying 62 passengers, including 40 Greeks, and eight crew when it disappeared. There were two babies and four children among the passengers, it said. One Greek construction company, Michaniki, said 23 of its employees had been on board the plane returning for Christmas from building works in Odessa. In one of a number of conflicting reports, a Ukrainian official said the plane was carrying 33 Greeks, 25 Ukrainians, two Poles, one German and one Russian and the eight-member Ukrainian crew. Aerosweet`s station manager in Athens, Efi Papachristopoulou, said the plane had not shown any sign of difficulty. Greek media said the plane had been flying at only 3,800 feet when last heard from, far lower than many of the mountains in the region. Civilians braved heavy rain and bitter cold to offer their help to the soldiers. Relatives of people aboard the missing plane rushed to Salonika airport to wait for news. There has been a long series of crashes involving former Soviet aircraft, both commercial and military. Accidents have been generally attributed to cash shortages which lower maintenance levels and place extra pressure on air crews.