Poland has scrambled fighter jets after Russia launched a barrage of drone and missile strikes into Ukraine.

The Operational Command of the Polish Armed Forces said “allied” aircraft joined the response to 99 Russian drones and missiles striking targets including thermal power plants.

Poland’s reaction is likely a response to a Russian cruise missile entering Polish airspace in recent weeks during an attack on Ukraine.

It is not clear which allies joined Poland, a Nato member, but fragments of a drone were reportedly found in Romania, also an alliance member, following an attack the previous day.

The Russian attacks on Friday hit three thermal plants in Ukraine. Ukraine’s largest private power company, DTEK, said that some of their equipment was “severely damaged”, in the latest aerial assault to target critical infrastructure.

The power grid operator Ukrenergo also said that both thermal and hydropower plants had been damaged in the attacks.

The country’s interior ministry said that the Russian assault had targeted 10 regions of the country, damaging power stations and private homes, and wounding six people.

“Eighty-four air targets were destroyed: 58 Shaheds and 26 missiles,” the air force said in a statement, referring to Iranian-designed attack drones routinely deployed by Russian forces.

“Last night Russia continued its barbaric attacks against the Ukrainian energy system. Emergency blackouts have been introduced in some regions,” Denys Shmyhal, the Ukrainian prime minister said, adding that energy facilities in six Ukrainian regions had been attacked.

“Ukraine needs more air defence systems to secure critical infrastructure and protect the population. This is the main topic of discussion with our international partners,” he said.

Last week, the Polish military announced that a Russian cruise missile had violated its airspace and spent 39 seconds in its territory.

Poland demanded an explanation from Moscow and said that it “remains on constant alert to ensure the safety of Polish airspace”.

Ukrainian television said that explosions were heard on Friday in the regions of Ivano-Frankivsk and Khmelnytskyi, as well as the city of Dnipro, as Russian cruise missiles were spotted in Ukrainian air space.

“Russia’s barbaric effort to take the power out for millions of men, women, and children continues unchecked,” said Bridget Brink, the US ambassador to Ukraine. “Our assistance is needed now.”

Romanian authorities found fragments of what appeared to be a drone on a farm near the Danube and the border with Ukraine on Thursday evening, the defence ministry said in a statement.