By Iryna Nazarchuk and Olena Harmash

ODESA, Ukraine (Reuters) - Russia launched a barrage of drones on Ukraine's southern city of Odesa, hitting energy infrastructure and leaving at least 160,000 people without heating in sub-zero temperatures, Ukrainian President Volodymyr Zelenskiy said on Wednesday.

The drone attack injured four people, including a child, and caused widespread power cuts, interrupting heating supplies to about 500 apartment buildings, 13 schools, a kindergarten, and several hospitals, officials said.

The temperature in the Black Sea port is currently about minus 6 degrees Celsius (21.2°F).

"Rescue operations are underway in Odesa after another Russian attack on the energy infrastructure," Zelenskiy said on the Telegram app.

"It is civilian energy facilities against which the Russian army has not spared neither missiles nor attack drones for almost three years."

The Ukrainian military said that Russia launched 167 drones during overnight attacks on the southern Odesa region and other regions across the country. Air defence units and mobile drone hunting groups shot down 106 of them, the military said.

It added that 56 drones were 'lost' in reference to the military using electronic warfare to redirect the unmanned aircraft.

Russia has stepped up its attacks on Ukrainian power infrastructure since March 2024, knocking out about half of the available generating capacity and causing widespread blackouts across the country.

Odesa Mayor Hennadiy Trukhanov said energy workers were assessing the situation in one of the city's largest residential districts after it lost power and heating.

Trukhanov said the "situation with heating was very difficult" and announced that schools and kindergartens in the district would not open on Wednesday.

The video he posted from the site showed buildings with damaged ceilings, windows, facades and doors.

“Everybody ran to the building hall. All the windows were blown out. The next hits scattered all the debris around. The furniture fell, the door was blown out as well," Tetiana, an Odesa resident who declined to share her last name, told Reuters.

"Even the ventilation in the bathroom was knocked down – and they say that a bathroom is a safe place. No, it is not.”

Russia says it does not deliberately target civilians, though thousands have been killed since it launched its full-scale invasion of Ukraine in February 2022.

(Additional reporting by Anastasiia Malenko in Kyiv; Editing by Kate Mayberry)