Overnight Ukrainian attacks knocked out power and heating in two large Russian cities close to the Ukrainian border, regional officials said Sunday, as both sides continue targeting each other’s energy infrastructure amid stalled peace efforts.

A drone strike caused temporary blackouts and disrupted heating in Voronezh, a city of over one million residents, regional Governor Alexander Gusev reported. Several drones were intercepted, but one hit a local utility site, sparking a fire that was quickly extinguished. Telegram channels suggested the strike targeted a thermal power plant.

In Belgorod, a missile strike late Saturday inflicted “serious damage” on power and heating systems, according to Governor Vyacheslav Gladkov, leaving about 20,000 households without service.

Russia’s Defense Ministry claimed its forces destroyed or intercepted 44 Ukrainian drones over the Bryansk and Rostov regions overnight but did not mention the strikes in Voronezh or Belgorod.

The attacks come as Moscow and Kyiv continue to exchange daily assaults on energy targets, with Ukraine seeking to cut Russia’s oil revenue through long-range strikes on refineries, while Russia tries to cripple Ukraine’s grid ahead of winter.

Meanwhile, Russia’s Foreign Minister Sergey Lavrov said Sunday he was ready to meet U.S. Secretary of State Marco Rubio to discuss ending the nearly four-year war and improving ties. Lavrov told state news agency RIA that peace was impossible without considering “Russian interests,” reiterating Moscow’s refusal to abandon its claim over Crimea, annexed from Ukraine in 2014.

The comments follow the Trump administration’s renewed push for a U.S.-brokered ceasefire, though little progress has been made since Presidents Donald Trump and Vladimir Putin last met in Alaska in August.

While Ukraine has expressed willingness for direct talks under Washington’s mediation, Western officials say Moscow continues using diplomacy to buy time as fighting grinds on.