Russia has launched a “major missile attack” on Ukrainian energy facilities and infrastructure with explosions reported in at least three cities.

Local authorities reported blasts in the capital, Kyiv, southern Kryvyi Rih and north-eastern Kharkiv as authorities sounded air raid alarms across the country warning of a new devastating barrage of the Russian strikes that have occurred intermittently since mid-October.

Kharkiv mayor Ihor Terekhov said on Telegram that the city is without electricity.

Kharkiv regional governor Oleh Syniehubov reported three strikes on the city’s critical infrastructure.

Kyrylo Tymoshenko, a senior official in President Volodymyr Zelensky’s office, reported a strike on a residential building in Kryvyi Rih, warning on Telegram: “There may be people under the rubble.” He said emergency services were on site.

Kyiv mayor Vitali Klitschko reported explosions in the north-eastern Desnianskyi and western Holosiivskyi district, urging residents to go to shelters.

“The attack on the capital continues,” he wrote on Telegram.

Subway services in the capital were suspended as residents flocked inside its tunnels deep underground to seek shelter.

Ukrzaliznytsia, the national railway operator, said power was out in a number of stations in the eastern and central Kharkiv, Kirovohrad, Donetsk and Dnipropetrovsk regions due to damage to the energy infrastructure.

But trains continued to run by switching from electric power to steam-engine power, which had been readied as a back-up.

Such strikes targeting energy infrastructure have been part of a new Russian strategy to try to freeze Ukrainians into submission after key battlefield losses by Russian forces in recent months.

But some analysts and Ukrainian leaders say such an onslaught has only strengthened the resolve of Ukrainians to face up to Russia’s invasion that began on February 24.

The previous round of massive Russian air strikes across the country took place on December 5. Ukrainian authorities have reported some successes in intercepting and downing incoming missiles, rockets and armed drones.