Complaining that the West is “stuffing Ukraine with weapons,” Russia pounded railroad stations and other supply-line points across the country Wednesday even as the European Union moved to further punish Moscow for the war by proposing a ban on oil imports, a crucial source of revenue.

The Kyiv Independent reported that on the evening of May 3 Russian missiles, fired mostly from the Caspian Sea, were “raining down” all over Ukraine.

The Russian military said Wednesday it used sea- and air-launched missiles to destroy electric power facilities at five railway stations across Ukraine, while artillery and aircraft also struck troop strongholds and fuel and ammunition depots. According to the Kyiv Independent, six train stations were struck. Several deaths and injuries were reported. 

An estimated 18 Russian missiles hit infrastructure sites across the country. Preliminary reports suggest that at least eight other missiles were downed by Ukraine’s Air Defense, the military said. At least one of those missiles was heading for the capital, Kyiv, but an adviser to the interior ministry, Anton Gerashchenko, said it was shot down. That could account for the sound of an explosion heard over the skies of the capital on Tuesday night, the Kyiv Independent reported. 

In southeastern Ukraine, heavy fighting raged at the Azovstal steel mill in Mariupol that represented the last pocket of Ukrainian resistance in the ruined southern port city, according to the mayor.

In his nightly video address, President Zelensky said that the strikes demonstrated that the Russian military is “nervously reacting to Ukraine’s successes,” which include a successful attempt to rout Russians forces in the strategic Kharkiv Oblast.

The flurry of attacks comes as Russia prepares to celebrate Victory Day on May 9, marking the Soviet Union’s defeat of Nazi Germany. The world is watching for whether Vladimir Putin will use the occasion to declare a victory or expand what he calls a “special military operation.”

A declaration of all-out war would allow the Russian dictator to introduce martial law and mobilize reservists to make up for significant troop losses.

The Kremlin spokesman, Dmitry Peskov, dismissed the speculation as “nonsense.”

As areas across Ukraine came under renewed attack, Belarus, which Russia used as a staging ground for its invasion, announced military exercises starting Wednesday. A top Ukrainian official said the country will be ready to act if Belarus joins the fighting.

The attacks on rail infrastructure were meant to disrupt the delivery of Western weapons, the Russian defense ministry spokesman, Major General Igor Konashenkov, said. Defense Minister Sergei Shoigu said the West is “stuffing Ukraine with weapons.”

The Western weaponry pouring into Ukraine helped its forces thwart Russia’s initial drive to seize Kyiv and seems certain to play a central role in the growing battle for the Donbas, the eastern industrial region that Moscow now says is its main objective.

The governor of the eastern Donetsk region, which lies in the Donbas, said Russian attacks left 21 people dead on Tuesday, the highest number of known fatalities since April 8, when a missile attack on the railway station in Kramatorsk killed at least 59.

On Tuesday, in one of the most crucial battles of the war, Ukrainian fighters said Russian forces began storming the bombed-out steel mill in Mariupol. The Kremlin said that was not true.

“There is no assault. We see that there are cases of escalation due to the fact that the militants take up the firing positions. These attempts are being suppressed very quickly,” Mr. Peskov said.

Over the weekend, more than 100 people — including women, the elderly, and 17 children — were evacuated from the plant during a cease-fire in an operation overseen by the UN and the Red Cross. The attacks on the plant soon resumed, and no further evacuations were organized.

It was unclear how many Ukrainian fighters were still inside, but the Russians put the number at about 2,000 in recent weeks, and 500 were reported to be wounded. A few hundred civilians also remained there, the Ukrainian side said.

Mariupol’s mayor, Vadym Boychenko, said that Russian forces were targeting the plant with heavy artillery, tanks, aircraft, warships, and “heavy bombs that pierce concrete three to five meters thick.”