KYIV, Ukraine — A massive barrage of Russian strikes on Monday morning hit critical infrastructure in Kyiv, Kharkiv and other cities, knocking out water and power supplies in apparent retaliation for what Moscow alleged was a Ukrainian attack on its Black Sea Fleet over the weekend.

The mayor of Ukraine’s capital said that 80% of consumers in Kyiv were left without water supplies “due to the damage to a power facility near” the city from Russian military strikes on Monday.

Local authorities were working on restoring the supplies as soon as possible, Mayor Vitali Klitschko said, telling Kyiv residents in the meantime to “stock up on water from the nearest pump rooms and points of sale.”

In a separate Telegram post, Klitschko added that water supplies in some areas of Kyiv will be restored in “three to four hours,” and power had already been restored in one of the city’s districts.

Loud explosions were heard across the Ukrainian capital in the early morning as residents prepared to go to work. Many received text messages from the emergency services about the threat of a missile attack, and air raid sirens wailed for three straight hours.

The attacks occurred just before Czech Prime Minister Petr Fiala and many top members of his government, including the foreign, defense and interior ministers, arrived in Kyiv in the latest show of support from European leaders for Ukraine.

Ukrainian Foreign Minister Dmytro Kuleba said there was no justification for Russia launching missiles meant to inflict so much suffering on civilians.

“Don’t justify these attacks by calling them a ‘response.’ Russia does this because it still has the missiles and the will to kill Ukrainians,” he tweeted.

There was a heavy military presence north of Kyiv. Smoke was rising from the left bank of the Dnieper River, either from a missile strike or where it was shot down by Ukrainian forces.

A resident of the area said he heard four loud explosions that rocked the area.

“At first I thought I heard a jet going by, but then I realized it was a missile,” said Serhii, who refused to give his full name. “The explosions were so loud! I consider myself experienced and prepared for attacks like this. But it was way too close and loud. I was frightened, really frightened.”

In the outlying region, authorities warned people to be prepared for a long power outage because of the emergency cuts. Kyiv region Gov. Oleksii Kuleba also said that one person was wounded and a number of houses were damaged as a result of the morning attack.

In the eastern city of Kharkiv, two strikes hit critical infrastructure facilities, according to authorities, and the subway ceased operating. Officials also warned about possible power outages in the city of Zaporizhzhia resulting from the strikes there.

The Lviv region in western Ukraine was also targeted, but the missiles were shot down, Lviv Gov. Maksym Kozytskyy said.

Critical infrastructure objects were also hit in the Cherkasy region southeast of Kyiv, and explosions were reported in other regions of Ukraine. In the Kirovohrad region of central Ukraine, the energy facility was hit, according to local authorities. In Vinnytsia, a missile that was shot down landed on civilian buildings, resulting in damage but no casualties, according to regional Gov. Serhii Borzov.

Some parts of Ukrainian railways were also cut off from power, the Ukrainian Railways reported.

The attack comes two days after Russia accused Ukraine of a drone attack against Russia’s Black Sea Fleet off the coast of the annexed Crimean Peninsula. Ukraine has denied the attack, saying that Russia mishandled its own weapons, but Moscow still announced halting its participation in a U.N.-brokered deal to allow safe passage of ships carrying grain from Ukraine.

Commenting on Monday’s attacks, the head of Ukraine’s presidential office Andriy Yermak said that Russian forces “continue to fight with civilian facilities.”

“We will persevere, and generations of Russians will pay a high price for their disgrace,” Yermak said.

The deputy head of the presidential office, Kyrylo Tymoshenko, said urgent power shutdowns were being carried out after “Russian terrorists once again launched a massive strike on energy facilities in a number of Ukrainian regions.”

It’s the second time this month that Russia unleashed a massive barrage of strikes on Ukrainian infrastructure. On Oct. 10, a similar attack rocked the war-torn country following an explosion on the Kerch Bridge linking annexed Crimea to mainland Russia — an incident Moscow blamed on Kyiv.

This time, however, the Ukrainian forces say they were able to intercept most of the missiles launched by Russia.

Ukraine’s air force said that more than 50 cruise missiles were launched from Tu-95/Tu-160 strategic aviation missile-carrying aircraft from the north of the Caspian Sea and from the area around the Russian city of Volgodonsk in the Rostov region. A total of 44 of them were shot down.

The Russian military hasn’t yet commented on the attack.