KINSHASA, Congo (AP) -- About a hundred people died in a train accident in Congo overnight in which seven cars flipped off the rails, officials in the Central African country said.

Rescue workers had pulled at least 70 bodies out of the wreckage by late Thursday, but others were still trapped under the rail cars, a witness told the country's U.N.-backed radio station, Radio Okapi.

The train's locomotive stopped responding to controls as it traveled between the cities of Ilebo and Kananga late Wednesday, leaving the conductor without a way to brake, said Medard Ilunga, head of Congo's state railway agency.

Seven cars overturned in the accident just before midnight, while another was leaning part way off the track Thursday, he said. Ilunga added that the conductor was able to detach the locomotive to go for help after the accident.

"The accident that occurred Wednesday resulted in a heavy toll of about 100 dead," government spokesman Toussaint Tshilombo Send told the Associated Press. Government reports and those of railway officials had previously put the death toll at about 30, with 27 wounded.

Send said the president had sent a mission to the site to help in the rescue effort and comfort the families. He added that an investigation will be mounted into the accident.

Injured passengers were being carried on people's backs and on bicycles to a hospital 10 kilometers (6 miles) away from the accident site, Radio Okapi reported.

The U.N. has sent helicopters with doctors, nurses and medical equipment to the site about 170 kilometers (100 miles) northwest of Kananga -- the capital of Congo's Kasai Occidental province, said Kemal Saiki, spokesman for the United Nation's peacekeeping operation in the Central African nation.

The United Nations has a large, established force in Congo to help the embattled country in its transition to democracy following decades of war and corrupt dictatorship.

Roads and rail are notoriously dilapidated in vast Congo -- a country the size of Western Europe. Most of Congo's railroads were built more than 100 years ago, when the country was a Belgian colony.