MOSCOW, Russia (CNN) -- At least 20 people were killed and 40 injured Friday as a result of a major road accident in southern Russia, officials said.
Regional health authorities, quoted by Russia's Interfax news agency, said the death toll stands at 21.
The head of the local Russian traffic police, Alexander Kaverzin, also quoted by Interfax, gave the same number. He said it included one child aged about 7 or 8, and he said at least one of the injured passengers is in very critical condition.
The crash occurred some 1,120 kilometers (700 miles) south of Moscow late Friday morning.
The collision between a large passenger bus and a gasoline tanker happened on a major highway near Samarskoye, a village 56 kilometers south of the city of Rostov-on-Don, according to a statement from the Russian Emergency Situations Ministry.
"The crash didn't lead to fire," the statement said. "According to preliminary information, 20 people died and another nine were hospitalized. Rescue workers, firemen and doctors are working on the site."
The bus was driving from the town of Kurgantsy to Taganrog via Rostov-on-Don when a truck traveling on the wrong side of the road and hit the bus head-on, according to Russian state TV news.
The bus could have been carrying up to 45 people, Russian TV said.
"Both cars have turned into a pile of metal, and we are getting conflicting reports about the number of casualties," Russian TV said. "It is difficult to count them, since injured people have been driven to various hospitals nearby by passing private cars."
Russia has Europe's worst road accident statistics. According to official numbers from the Russian traffic police, in 2008 almost 30,000 people were killed in car crashes across the country and more than 270,000 were injured.