(NewsNation) — Russian forces continued attacking eastern Ukraine on Saturday, including the city of Lysychansk, where they shelled an oil refinery and ignited a large fire in the territory.

Luhansk Regional Governor Serhiy Haidai said it wasn’t the first time the refinery had been targeted. He accused Russians of trying to exhaust local emergency services. As a result of the shelling, “the remains of oil sludge” were burning, he said.

Russia reportedly has been focusing on eastern Ukraine after facing stiff resistance in other areas.

But even as Russian President Vladimir Putin’s army pivots toward a new offensive in the east, they resumed attacks on Kyiv and western Ukraine on Saturday — a reminder to Ukrainians that the whole country remains under threat.

Ukrainian President Volodymyr Zelenskyy raised further concerns Friday that Russia could turn to using nuclear weapons to seek revenge after Ukrainian forces sank the Russian Navy’s flagship vessel in the Black Sea.

Retired U.S. Lt. Gen. Richard Newton said Saturday on “NewsNation Prime” that the sinking of the vessel was a “huge deal” because the ship was the largest to have sunk in combat since World War II.

“It’s the first of the flagships that have ever been sunk, Russian flagship, since 1905,” Newton said. “So this was extraordinary, this was the Russian flagship of the Black Sea fleet.”

CIA Director William Burns said the threat of nuclear war cannot be taken lightly, but there has not been much “practical evidence” of the use of nuclear weapons seen yet.

Newton said the sinking of the ship in the Black Sea will likely push the Russian fleet farther out to sea as it will want to get out of range from the missiles that sank the vessel. This could mean Russian artillery from the ships could no longer reach the Ukrainian coast.

The war may take years to end, Newton predicted, as he believes it is still on a path of escalation and will be “a long war of attrition.”

“The United States and NATO need to be pouring in arms, shipment of arms, high-powered arms, into the hands of the Ukrainian military,” Newton said.

Ukraine’s presidential office reported Saturday that missile strikes and shelling over the past 24 hours occurred in eight regions: Donetsk, Luhansk and Kharkiv in the east, Dnipropetrovsk, Poltava and Kirovohrad in central Ukraine and Mykolaiv and Kherson in the south.

Smoke could be seen rising early Saturday from eastern Kyiv. Mayor Vitali Klitschko reported a strike on the city’s Darnytskyi District, where one person died and several more were wounded.

“Our air defense forces are doing everything they can to protect us, but the enemy is insidious and ruthless,” Klitschko said on the Telegram messaging app.

Russia’s Defense Ministry said the attacks targeted an armored vehicle plant in the Ukrainian capital.

The mayor urged Ukrainians not to return to Kyiv just yet, as strikes on the city are likely to continue.

“We can’t prohibit, we can only recommend. If you have the opportunity to stay a little bit longer in the cities where it’s safer, do it,” he said.

Newton said “atrocities will only continue to mount” against Ukrainian citizens as Russia continues to try and landlock the country and push further.

Kharkiv, Ukraine’s second-largest city, was hit by an explosion believed to be caused by a missile. The strike, which happened near an outdoor market along with residential and industrial buildings, killed one person and wounded at least 18.

Meanwhile, the governor of the Lviv region reported airstrikes on the region by Russian Su-35 aircraft that took off from neighboring Belarus. That area — far from the Russian border— had long been seen as a safe zone.

In Oleksandriya, a city in Ukraine’s Kirovohrad region, Russian forces hit an airfield with a missile strike. Overnight shelling in the eastern Luhansk region killed one person, wounded three and damaged gas pipelines, according to Haidai.

This all comes a day after U.S. officials confirmed that the flagship of Russia’s Black Sea fleet sank after being struck by two Ukrainian Neptune missiles earlier this week.

The Soviet-era guided-missile cruiser known as the Moskva sank after being hit by two Ukrainian cruise missiles about 60 nautical miles south of Odesa, a senior defense official told NewsNation.

Russia’s military command had warned of renewed attacks on Ukraine’s capital in the aftermath of what they alleged were Ukrainian strikes on Russian territory.

Russia’s invasion of Ukraine started Feb.24, causing millions to flee the country. The United Nations Human Rights Office said it has confirmed the deaths of 1,982 civilians, but warned that the actual number of deaths will be considerably higher.

Associated Press reporters this week documented civilian deaths in strikes on Kharkiv. Each day has brought new discoveries of civilian victims of the war that started in February.

In the Kyiv region alone, Ukrainian authorities reported finding 900 civilian bodies, most shot dead, after Russian troops’ retreat.

Ukrainian President Volodymyr Zelenskyy said officials think 2,500 to 3,000 Ukrainian troops have died in the war. About 10,000 have been injured, he told CNN in an interview.

“It’s hard to say how many will survive,” he said.

While the U.S. and its allies have responded to Russia’s attacks with sanctions on the country, Putin and oligarchs, Zelenskyy said that they are not yet enough to stop the Russian military.

He called on “the democratic world” to ban Russian oil. It’s a move U.S. President Joe Biden and U.S. lawmakers made, but Europe relies more heavily on Russian energy.

Russia has criticized these sanctions, and barred UK Prime Minister Boris Johnson and his predecessor, Theresa May, from entering the country Saturday.

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