Russia unleashed a massive missile barrage on cities across Ukraine early on Thursday, targeting energy infrastructure facilities, Ukrainian officials and media said.

Ukrainian officials said residential buildings were hit but did not immediately say if there were casualties.

Air raid sirens wailed for hours across Ukraine, including the capital, Kyiv, where residents were jolted out of bed by explosions.

It was not immediately clear how many missiles had struck targets in Kyiv, or whether the sounds were missiles being intercepted by defence systems, which were activated in multiple regions of the country.

Kyiv Mayor Vitali Klitschko said explosions were reported in the city’s Holosiivskyi district and emergency services were heading there.

In eastern Ukraine, 15 missiles struck Kharkiv and the outlying northeastern region, hitting residential buildings, according to Kharkiv Governor Oleh Syniehubov.

He promised to reveal more details about the scale of the damage or any casualties in Ukraine’s second-largest city.

“Objects of critical infrastructure is again in the crosshairs of the occupants,” he said in a Telegram post.

Kharkiv Mayor Ihor Terekhov reported on Telegram that there were “problems with electricity” in some parts of the city.

The governor of the southern Odesa region, Maksym Marchenko, also reported strikes on Odesa, saying that energy facilities and residential buildings were hit.

“The second wave is expected right now, so I ask the residents of the region to stay in shelters!” Mr Marchenko wrote on Telegram.

Ukrainian Railways reported power outages in certain areas. Five trains were delayed by more than one hour, and 10 trains were delayed by more than 30 minutes.

Preventive emergency power cuts were applied in Kyiv, Dnipropetrovsk, Donetsk and Odesa regions, supplier DTEK said. Mr Klitschko says 15% of the capital’s energy consumers were without power due to the emergency power cuts.

More explosions were reported in the northern city of Chernihiv and the western Lviv region, as well as in the cities of Dnipro, Lutsk and Rivne. Ukrainian media also reported explosions in the western regions of Ivano-Frankivsk and Ternopil.

Russia has been hitting Ukraine with these massive missile attacks since last October. Initially, the barrages targeting the country’s energy infrastructure took place weekly, plunging the entire cities into darkness, but became more spread out in time, with commentators speculating that Moscow may be saving up ammunition.

The last massive barrage took place on February 16.