Attacks leave thousands without power in Ukraine amid new peace talks

"The intensity of the attacks is very high, and the Russians are trying to make the most of the shortage of ballistic missile interceptors," Zelensky said.

The new attacks come as Russia, Ukraine and the United States try to advance negotiations to end the conflict.

The next round of negotiations to try to end the war should begin in a trilateral format, with representatives from Russia, Ukraine and the United States, said this Sunday Yuri Ushakov, Kremlin's foreign policy advisor, according to the Interfax agency.

Asked about the possible participation of European countries in the negotiations, Ushakov stated: "We have working contacts with the Americans. Therefore, it is logical that at least the first rounds of negotiations will be held in a trilateral format."

Ushakov also stated that Russian President Vladimir Putin would answer a possible call from Zelensky and said that the Russian leader never refused to engage in dialogue.

An industrial facility in the Russian region of Nizhny Novgorod suffered significant damage after a large-scale drone attack, local governor Gleb Nikitin said on Sunday. He did not give the name of the facility and said emergency services were called.

The region is home to the NORSI oil refinery, one of the largest in Russia. However, in the information provided so far, there is no confirmation that the refinery was the installation affected.

Authorities in Nizhny Novgorod said they were taking measures to maintain fuel supplies at gas stations in the region following the attack, according to Russian state agency TASS.

Russian investigators have opened a criminal case on suspicion of terrorism related to the attack on the industrial facility and civil infrastructure in the region, TASS reported, citing Russia's Investigative Committee.