By Olena Harmash

KYIV (Reuters) -Russian drones hit infrastructure facilities in Ukraine in an overnight assault that caused power outages in more than 400 towns and villages in the south, southeast, and north of the country, Ukrainian officials said on Saturday.

President Volodymyr Zelenskiy congratulated the air force for shooting down what it said were 29 out of 38 Iranian-made Shahed drones in several Ukrainian regions between 8 p.m. (1800 GMT) on Friday and 4 a.m. on Saturday.

"Your accuracy, guys, is literally life for Ukraine," Zelenskiy said in his nightly video address, but warned: "The closer we are to winter, the more Russians will try to make the strikes more powerful."

Last winter, Russia pounded Ukraine with hundreds of missiles and drones, leaving millions without electricity, heating and water during the coldest months.

The energy ministry said there was enough electricity in the system to meet the country's needs but that the drone strikes deprived 1,550 consumers of power because of damage to the grid.

It said earlier that 416 settlements in the Odesa region in the south and in the Zaporizhzhia region in the southeast had been cut off due to the strikes.

This year Ukraine had an unusually warm autumn. But as temperatures start to fall, officials have urged residents and businesses to prepare for renewed Russian attacks.

"We do not have a right to relax," Volodymyr Kudrytskiy, head of the power grid operator Ukrenergo, told Ukrainian TV.

"Certainly, all of us, energy workers and defence forces, are preparing to repel possible Russian attacks on the energy infrastructure this winter."

The energy ministry said an oil refinery was hit in the Odesa region. An administrative building was also damaged and one civilian was wounded in the strike, the south military command said in a statement on the Telegram messaging app.

In the northern Chernihiv region, on the border with Russia and Belarus, two infrastructure buildings were damaged during the overnight strike, the military said.

The energy ministry said six settlements were without power in the Chernihiv region.

The drones also targeted Kyiv in the second attack so far this month, officials said, adding that all drones heading to the capital were shot down on their approach.