Severe winter weather has claimed 18 lives in Ukraine since the start of the month and three babies were born in traffic jams on snow- and ice-snarled roads, authorities said Monday.

Twelve people have died since Friday as temperatures plunged to minus 15 degrees Celsius (five Fahrenheit) in some parts, the health ministry's press office said.

Another 133 people sought medical treatment for hypothermia and frostbite, with 108 of them hospitalised.

Near the western city of Lviv on Monday, a woman gave birth to twins in an ambulance blocked on the road, the regional office of the ministry for emergency situations said.

The mother and her babies were eventually taken to in a nearby hospital.

In nearby Rivne on Sunday, another woman gave birth in her snowbound car, three kilometres (two miles) from the village of Kysorychi.

Cars were blocked for 18 kilometres (11 miles) overnight Saturday on the main road between the capital Kiev and Lviv, officials said.

An opposition deputy claimed traffic was backed up for 40 kilometres.

Rescuers dug about 1,800 cars out in the country's western regions on Sunday, when more than 18,000 people joined snow clearing efforts.

Regional authorities in Lviv said road conditions between Kiev and Lviv were back to normal on Monday.