KYIV, Ukraine — Russia on Sunday launched a massive drone and missile attack on Ukraine, described by officials as the largest in recent months, targeting energy infrastructure and killing civilians.

Hours later, President Joe Biden authorized for the first time the use of U.S.-supplied long-range missiles by Ukraine to strike inside Russia, after extensive lobbying by Ukrainian officials.

The weapons are likely to be used in response to North Korea’s decision to send thousands of troops to support Russia in the Kursk region where Ukraine mounted a military incursion over the summer.

It is the second time the U.S. has permitted the use of Western weapons inside Russian territory within limits after permitting the use of HIMARS systems, a shorter-range weapon, to stem Russia’s advance in Kharkiv region in May.

President Volodymyr Zelenskyy said that Russia had launched a total of 120 missiles and 90 drones in a large-scale attack across Ukraine. Various types of drones were deployed, he said, including Iranian-made Shaheds, as well as cruise, ballistic and aircraft-launched ballistic missiles.

Ukrainian defenses shot down 144 out of 210 air targets, Ukraine’s air force reported later on Sunday.

“The enemy’s target was our energy infrastructure throughout Ukraine. Unfortunately, there is damage to objects from hits and falling debris. In Mykolaiv ... two people were killed and six others were injured, including two children,” Zelenskyy said.

The combined drone and missile attack was the most powerful in three months, according to the head of Kyiv’s City Military Administration, Serhii Popko.

A thermal power plant operated by private energy company DTEK was “seriously damaged,” the company said.

Explosions were heard across Ukraine on Sunday, including in the capital, Kyiv, the key southern port of Odesa, and the country’s west and central regions, according to local reports.

The operational command of Poland’s armed forces wrote on X that Polish and allied aircraft, including fighter jets, have been mobilized in Polish airspace because of the “massive” Russian attack on neighboring Ukraine. The steps were aimed to provide safety in Poland’s border areas, it said.

Russia’s Defense Ministry on Sunday acknowledged carrying out a “mass” missile and drone attack on “critical energy infrastructure” in Ukraine, but claimed all targeted facilities were tied to Kyiv’s military industry.

Although Ukraine’s nuclear plants were not directly impacted, several electrical substations on which they depend suffered further damage, the U.N.’s nuclear energy watchdog said in a statement Sunday. According to the International Atomic Energy Agency, only two of Ukraine’s nine operational reactors continue to generate power at full capacity.

Ukrainian drones also struck Russia.

A local journalist died Sunday as Ukrainian drones hit Russia’s embattled Kursk region, its Gov. Aleksei Smirnov reported.

Moscow’s forces have for months strained to dislodge Ukrainian troops from the southern province after a bold incursion in August that constituted the largest attack on Russia since World War II and saw battle-hardened Ukrainian units swiftly take hundreds of square miles of territory.

In Russia’s Belgorod province, near Ukraine, a man died after a Ukrainian drone dropped explosives on his car, local Gov. Vyacheslav Gladkov reported.

Another Ukrainian drone on Sunday targeted a drone factory in Izhevsk, deep inside Russia, according to anti-Kremlin Russian news channels on the Telegram messaging app. The regional leader, Aleksandr Brechalov, reported that a drone exploded near a factory in the city, blowing out windows but causing no serious damage.

When Russian tanks rolled into Ukraine in February 2022, the conventional wisdom was that the capital would soon fall and the rest of the country wouldn’t last long against a larger enemy.

Instead, it was that narrative that quickly collapsed. The Ukrainian army proved it could slow the advance of Russia’s forces and, if not drive them out completely, then — with enough support from the West — at least forestall defeat.

But nearly three years later, the outlook is again grim. Russia is expending huge amounts of weaponry and human life to make small-but-steady territorial gains to the nearly one-fifth of Ukraine it already controls. Ukraine, meanwhile, is struggling to minimize losses, maintain morale and convince allies that, with more military aid, it can turn the tide.

As this brutal war of attrition grinds toward its 1,000th day on Tuesday, neither side seems eager to negotiate. President-elect Donald Trump has said he could quickly end the war, although it is unclear how or in whose favor he might tip the scales.

This backdrop appears to be driving Russia’s strategy in eastern Ukraine, according to Phillips O’Brien, a professor of strategic studies at the University of St. Andrews, Scotland.

Trump could try to force an end to the war by halting the supply of weapons to Ukraine.

“If Trump cuts aid to Ukraine and a cease-fire leads to a frozen conflict, Russia wants to secure as much territory as it can now,” O’Brien said.

For Ukraine, the key to a cease-fire would be guarantees from the West that it won’t allow Russia to re-invade. Otherwise, O’Brien said, “a cease-fire is a recipe for constant instability in Europe.”