Russian air strikes killed 35 people at a military base outside Ukraine's western city of Lviv, the regional governor said Sunday, updating the toll from nine previously.

"I have to announced that, unfortunately, we have lost more heroes: 35 people died as a result of the shelling of the International Peacekeeping and Security Centre," the governor of Lviv region Maxim Kozitsky wrote on Telegram.

Earlier, nine people have been killed by a Russian airstrike on the Black Sea city of Mykolaiv near the strategic port of Odessa, the regional governor Vitaliy Kim said Sunday.

"Scum!!!!!! 9 people died as a result of the bombing by assholes. Mykolaiv," Kim wrote on Telegram.

Kim wrote earlier that according to preliminary information, the Russians bombed a gas turbine factory in the city on Sunday morning.

The local authorities announced an air raid warning early Sunday.

"We have freedom and we are fighting for it," the governor wrote.

Mykolaiv, a city of around 500,000 which lies on the road to Odessa around 100 kilometres (62 miles) away, has been under attack by Russian troops for days and many residents have fled due to the heavy bombardment.

For several days now, Ukrainian forces have managed to hold off the besieging Russian troops.

An AFP reporter said a cancer treatment hospital and an eye clinic there came under fire Saturday.