Russia and Ukraine on Wednesday exchanged hundreds of prisoners of war in the biggest single release of captives since Russia’s full-scale invasion in February 2022.

Ukrainian authorities said that 230 Ukrainian prisoners of war returned home in the first exchange in almost five months. Russia’s Defense Ministry said that 248 Russian servicemen have been freed under the deal sponsored by the United Arab Emirates.

There was no immediate acknowledgment from the UAE, which has maintained close business ties to Moscow throughout Russia’s war on Ukraine.

Ukraine’s Human Rights Ombudsman, Dmytro Lubinets, said it was the 49th prisoner exchange during the war.

Some of the Ukrainians had been held since 2022. Among them were some of those who fought in milestone battles for Ukraine’s Snake Island and the Ukrainian city of Mariupol.

Russian officials offered no other details of the exchange.

Also Wednesday, Russia said it shot down 12 missiles fired at one of its southern regions bordering Ukraine, as Kyiv’s forces seek to embarrass the Kremlin and puncture President Vladimir Putin’s argument that life is going on as normal despite the fighting.

The situation in the border city of Belgorod, which came under two rounds of shelling on Wednesday morning, “remains tense,” said regional Gov. Vyacheslav Gladkov, writing on Telegram.

“Air defense systems worked,” he said, promising more details about possible damage after inspecting the area later in the day, part of a New Year’s holiday week in Russia.

Ukraine fired two Tochka-U missiles and seven rockets at the region late Tuesday, followed by six Tochka-U missiles and six Vilkha rockets on Wednesday, the Russian Defense Ministry said.

The Soviet-built Tochka-U missile system has a range of up to 120 kilometers (75 miles) and a warhead that can carry cluster munitions. Ukraine has received some cluster munitions from the United States but the Tochka-U and Vilkha can use their own cluster munitions.

The Russian side of the frontier has come under increasingly frequent attack in recent days. Throughout the war, border villages have sporadically been targeted by Ukrainian artillery fire, rockets, mortar shells and drones launched from thick forests where they are hard to detect.

Lately, as Russia fired missiles and drones at Ukrainian cities, Kyiv’s troops have aimed at Belgorod’s regional capital, which is about 100 kilometers (60 miles) north of Kharkiv, Ukraine’s second-largest city.

Belgorod, with a population of about 340,000, is the biggest Russian city near the border. It can be reached by relatively simple and movable weapons such as multiple rocket launchers.

On Saturday, shelling of Belgorod killed 25 people, including five children, in one of the deadliest strikes on Russian soil since Moscow’s full-scale invasion. Another civilian was killed Tuesday in a new salvo.

Hitting Belgorod and disrupting city life is a dramatic way for Ukraine to show it can strike back against Russia, whose military outnumbers and outguns Kyiv’s forces.

The tactic appeared to be having some success, with signs the attacks are unsettling the public, political leaders and military observers.

On Monday, Putin lashed out against the Belgorod attacks by Ukraine. “They want to intimidate us and create uncertainty within our country,” he said, promising to step up retaliation.

Answering a question from a soldier who asked him about civilian casualties in Belgorod, Putin said: “I also feel a simmering anger.”

Many Russian military bloggers have expressed regret about Moscow’s withdrawal from the border area in September 2022 amid a swift counteroffensive by Kyiv, and they have argued that more territory must be seized to secure Belgorod and other border areas.

Russia describes Ukrainians as “terrorists” who indiscriminately target residential areas while insisting Moscow only aims at depots, arms factories and other military facilities — even though there is ample evidence that Russia is hitting Ukrainian civilian targets.

Ukrainian officials rarely acknowledge responsibility for strikes on Russian territory.

In another Russian border region on Wednesday, the city of Zeleznogorsk was briefly cut off from the power grid after Ukrainian shelling, local officials said.

Authorities were forced to temporarily shut down an electricity substation in the city of 100,000 people in the Kursk region to repair the damage from an aerial attack, Kursk Gov. Roman Starovoit said on Telegram.

Residents were without power or heat, he said, although electricity was restored in most of the city about two hours later, he said.

Russia has recently intensified its long-range attacks on Ukrainian cities, including using Kinzhal missiles which can fly at 10 times the speed of sound. The Kremlin’s forces appear to be targeting Ukraine’s defense industry, the U.K. Defense Ministry said Wednesday.

The onslaught has prompted Kyiv officials to ask its Western allies to provide further air defense support.

NATO announced Wednesday that it would help member nations buy up to 1,000 surface-to-air Patriot guided missiles in a deal possibly costing about $5.5 billion. That could allow alliance members to send more of their own defense systems to Ukraine.