Ukrainian President Volodymyr Zelensky appealed for additional support from the United States on Tuesday after Russia launched one of its deadliest attacks in months, with at least 22 people killed and dozens injured.

“Europe needs its own anti-ballistic defense so that this war can finally be brought to an end,” urged Zelensky. “Assistance from the United States in supplying missiles for patriot systems is absolutely necessary.”

Overnight, Russia “launched 656 attack drones and 73 missiles of various types” at Ukraine, Zelensky said.

“If Ukraine is not protected from ballistic and other missile strikes, these attacks will continue,” he argued, as he reiterated his calls for additional assistance. “We are counting on the support of our partners and on effective responses to today’s attack”

Zelensky said Russia’s attack primarily struck the capital Kyiv, "where dozens of residential buildings and other purely civilian infrastructure were damaged again," and the central-eastern city of Dnipro.

The death toll in Kyiv stands at six, with over 70 people injured, according to a statement from Ukraine’s Ministry of Internal Affairs. Local rescuers are continuing operations throughout the city’s districts.

The strikes temporarily cut power to 140,000 residents in Kyiv, according to energy company DTEK. Two engineers were injured while moving to shelter. Electricity has since been restored for the majority. 

In Dnipro, the death toll was estimated to be 16, with over 40 people sustaining injuries, said regional governor Oleksandr Hanzha. 

Ukraine’s state-owned oil and gas company Naftogaz reported one of its key facilities in the northeastern Kharkiv region had been hit. 

“This is a deliberate tactic of terror. This is how Russian forces are attempting to inflict maximum damage not only on infrastructure, but also on the people who are rescuing, repairing, and rebuilding,” said Sergii Koretskyi, CEO of Naftogaz Group.

Ukraine’s Air Force described the overnight assault as a “massive air attack,” saying Russia launched 729 aerial targets, including ballistic missiles and Shahed-type drones.

Russia’s Defense Ministry said the strikes were retaliation for what it described as “terrorist acts” carried out by Ukraine.

Russian President Vladimir Putin had vowed to seek retaliation after accusing Kyiv of carrying out an attack on a student dormitory in a Russia-controlled part of eastern Ukraine on May 22.

Ukraine's military said it had struck an elite drone command unit in the area. Andrii Melnyk, Ukraine’s ambassador to the United Nations, denied the allegation related to the dormitory last week, calling it a “fake story” and a Russian "propaganda narrative" during a U.N. Security Council meeting. 

Putin’s spokesperson has since said that the war is facing “a completely different paradigm.”

On Tuesday, local officials in Russia’s southern ⁠Krasnodar region reported that the Ilsky oil refinery was on fire after it was struck by overnight Ukrainian attacks. The fire has since been put out. 

Kyiv has targeted a number of oil refineries in Russia as of late. Ukrainian officials have said the strikes are intended to disrupt Moscow’s war financing capacity rather than solely battlefield targets, as the facilities are central to Russia’s export economy. 

The latest escalation in the conflict follows one of Russia’s heaviest bombardments of the war in May.

Since then, Zelensky has reiterated the need for further Western support. 

Last week, he sent a letter to U.S. President Donald Trump and members of Congress requesting additional air defense systems.

“There is not enough anti-ballistic missile production in the United States and this could lead to a crisis in different parts of the world,” Zelensky said. “Russia is ramping up its internal production of ballistic missiles. I sent a letter to the White House and to the U.S. Congress. I hope they will understand and respond.”

Ukraine’s Foreign Minister Andrii Sybiha has also urged allies to take “concrete steps.”

"Peace efforts will only succeed when they are backed with real pressure on Moscow," he argued, calling for tougher sanctions and expanded military support.

European leaders condemn deadly strikes and call for action

European officials have united in condemning the latest wave of attacks on Ukraine and vowed to stand together in the face of Russian aggression.

“The European Parliament remains firmly on Ukraine’s side, as it has since 24 February 2022,” the institution's press service told TIME on Tuesday. “It is unwavering in its solidarity with the Ukrainian people who, since 2014, have paid the highest price in defending their country’s sovereignty and territorial integrity, and in protecting Europe and its shared democratic values and principles.”

A spokesperson for the European Commission emphasized the E.U.'s financial support of Ukraine in a statement to TIME and said it will keep "pressure on Russia, namely through sanctions" as "Russia’s overheated war economy is coming to its limits."

Elsewhere, Estonian Foreign Minister Margus Tsahkna said of the overnight strikes: “Russia continues its systematic hunt for civilian lives. This is Moscow’s calculated strategy of terror. Only firm, uncompromising pressure and complete international isolation can restrain an aggressor that recognizes no limits.”

Tsahkna insisted that “Russia must pay” and warned “every softened response becomes an invitation for the next strike.”

Lithuanian Foreign Minister Kęstutis Budrys issued a similarly strong rebuke, describing it as a “horrific night."

“Ukraine does not need more statements of condemnation. It needs action,” he said, calling for increased military support for Kyiv and maximum economic pressure on Russia.

Dutch Defense Minister Dilan Yeşilgöz-Zegerius lamented what she described as Putin’s “brutal violence against innocent civilians” and reaffirmed that the Netherlands “will continue to support Ukraine.”

Spanish Foreign Minister José Manuel Albares echoed that message, stating that "Russia must stop its aggression, respect international humanitarian law, and accept negotiations for a peace in accordance with the U.N. Charter."

The U.K. also issued a strong condemnation of the latest attacks, with Defense Secretary John Healey saying Britain “will stand firm with Ukraine.”

Former British Prime Minister Boris Johnson argued that Putin was “behaving with the desperate barbarism of a man who is going to lose.”

“He will never conquer Ukraine. He needs to admit that to himself—and save many thousands of lives on both sides,” he added.

European officials have been particularly alarmed by the increasingly escalatory nature of the conflict since a Russian strike hit an apartment building in eastern Romania last week—a crash E.U. leaders described as “a serious violation of Romania’s sovereignty and European airspace.”