Explosions heard in Kyiv as Russian forces claim to attack missile factory

April 15 (UPI) -- Powerful explosions shook the Ukrainian capital of Kyiv on Friday -- the 50th day of fighting since the war began -- as Russian forces said they attacked a plant there that manufactured missiles.

The explosions on Friday were the most powerful in Kyiv since Russian troops largely withdrew from the area two weeks ago.

The attack is believed to be retaliation by Moscow for purported Ukrainian attacks on Russian soil. Russian officials said that they hit a "military factory" in the capital.

The attack came one day after Ukrainian leaders said that forces had sunk Russia's flagship in the Black Sea, the Moskva.

Russian defense ministry spokesman Maj. Gen. Igor Konashenkov threatened more bombings for various targets -- including Kyiv's "decision-making centers" -- because of Ukrainian counterattacks.

"As a result of the strike on the Zhuliany Vizar machine-building plant workshops for the production and repair of long-range and medium-range anti-aircraft missile systems were destroyed, as well as anti-ship missiles," Konashenkov said, according to CNN.

Konashenkov said the attack was ordered because of Ukraine's attempts at "sabotage and strikes" on Russian territory.

The sinking of the Moskva was a significant setback for Russian President Vladimir Putin's war in Ukraine, as it was one of the Russian navy's most formidable warships.

Russian officials, who have produced an avalanche of disinformation since the war began on Feb. 24, claimed that the ship sank due to a fire on board. They said nothing about a Ukrainian attack.

Ukrainian soldiers walk through destroyed Russian military machinery in the recaptured city of Bucha, northwest of Kyiv in Ukraine on April 4. Photo by Vladyslav Musienko/UPI

On Friday, Ukraine's defense ministry celebrated the sinking of the Moskva.

"We have one more diving spot in the Black Sea now," the ministry said according to The Washington Post.

Now eight weeks into the war, Moscow was said to be close on Friday to capturing Mariupol -- which would be its first major city since the fighting began. Russian troops, the reports said, have separated the last two remaining factions of Ukrainian resistance in the city.

Russian troops are now controlling those who enter and exit the city and Mariupol Mayor Vadym Boichenko said they have taken some Ukrainian troops as prisoners. He denied a mass surrender by Ukrainian troops, which Russia claimed this week.

The last Ukrainian forces in Mariupol have continued to fight at the city's important port and a steel factory. Much of Mariupol has been heavily damaged by Russian bombardment and Boichenko said more than 20,000 civilians have been killed there. That casualty count was not immediately verifiable, as the United Nations said this week that around 2,000 civilians have been killed in the war so far.

Also Friday, Russian forces continued shelling the separatist-held Donbas region in eastern Ukraine. Donetsk military leader Pavlo Kyrylenko said that "almost all settlements of the Donetsk region along the front line are under attack."

Kyrylenko said that roughly a dozen civilians have been killed in Maryinka and more than 100 homes have been damaged. Russian forces said earlier this week that they had taken parts of Popasna.