At least 14 Russians were killed and 29 injured in a bus crash in Ukraine`s northern Chernigov region Saturday morning, Russian authorities said, according to Xinhua.

President Vladimir Putin expressed his condolences to the families of the bus crash victims.

Presidential press secretary Dmitry Peskov told local media that Putin instructed the government to "take all possible measures to provide timely assistance to those in need."

Prime Minister Dmitry Medvedev ordered the Health Ministry and the Emergency Situations Ministry to offer help to the injured passengers. He also expressed compassion to relatives of the victims.

Health Minister Veronika Skvortsova said that of the 29 injured Russians, five remained in serious condition and one was in critical condition.

The accident occurred when a bus carrying more than 40 Russian pilgrims to a monastery overturned after crossing into another lane on the Chernigov-Kiev highway, the authorities said. The driver lost control of the bus before it overturned.

Vladimir Stepanov, crisis management chief of the emergency ministry, told local media that an Il-76 medical plane left for Ukraine at 11: 00 a.m. Moscow time (0700 GMT) to take the injured back for treatment. Another Yak-42 with medical staff and specialists on board set off later.

Citing doctors in the hospital, a Ukrainian official said some of the injured were too weak to be returned to Russia, adding three people had undergone operations.

Russian Emergency Situations Ministry put the death toll at 14, after a preliminary report said 15 Russians were killed.

Ukrainian Emergency Ministry later confirmed 14 deaths and 29 injuries of a total of 43 people on the bus.

A list of passengers onboard will be published on the Russian ministry`s website.

A preliminary investigation of the crash indicated the driver had fallen asleep and steered the bus into the oncoming lane before he lost control of the vehicle, the authorities said.