Russian troops pushed closer to the center of the eastern Ukrainian city of Syevyerodonetsk on May 31, in a street-by-street battle with Kyiv’s forces that has left most of the city in ruins.

Ukrainian President Volodymyr Zelenskiy said the situation in the eastern Ukrainian region of Donbas, which has been under bombardment for weeks, was “extremely difficult” as Russia has put its military’s “maximum combat power” there.

Leonid Pasechnik, a Moscow-backed separatist leader in Ukraine’s eastern Luhansk region, told TASS that a third of Syevyerodonetsk was “already under our control” but the Russians’ advance was less rapid than hoped.

As Moscow’s advance on Syevyerodonetsk increased in intensity, Russian forces also shelled parts of Ukraine’s northeast.

“The situation in Donbas remains extremely difficult. The Russian Army is trying to gather overwhelming forces in certain areas to put more and more pressure on our defenders. There, in the Donbas, the maximum combat power of the Russian Army is now gathered,” Zelenskiy said in his nightly address late on May 30.

But Ukrainian forces drove the Russians out of the village of Toshkivka to the south, Kyiv said, potentially frustrating Moscow’s push to encircle the area.

The Ukrainian Army also said its forces had pushed back Russian troops to defensive positions in the villages of Andriyivka, Lozove, and Bilohorka on the southern bank of the Inhulets River, which forms the border of Kherson Province, where Moscow is trying to consolidate control.

Ukraine’s General Staff said in a statement, “the enemy suffered losses and withdrew from the village of Mykolayivka, [in the] Kherson region, which led to panic among servicemen of other units of the armed forces of the Russian Federation.”

The information could not pe independently verified, but if Russian forces have withdrawn from Mykolayivka, it would mark a gain of several kilometers for Ukrainian units.

The Russian advance in Syevyerodonetsk and Lysychansk on either side of the strategically important Siverskiy Donetsk River is part of an all-out push that has been portrayed as part of a race against time for the Kremlin.

The cities are key to Russian efforts to complete the capture of the Donbas before more Western arms arrive to bolster Ukraine’s defense.

Zelenskiy spoke with EU leaders on May 30, telling them they must show strength as they worked toward adopting a new set of sanctions.

“Europe needs to show strength because Russia only sees strength as an argument,” Zelenskiy said on May 30 in a video speech to an EU summit intended to reinforce the bloc’s support for Ukraine.

EU divisions over Russian oil imports slowed the adoption of a new sanctions package, but late on May 30 European Union leaders agreed to ban most oil imports. They also agreed to the removal of Russia’s Sberbank from the SWIFT messaging system, a ban on three more Russian state-owned broadcasters, and sanctions against individuals responsible for war crimes.

The EU has rolled out five packages of sanctions against Russia since its troops invaded Ukraine on February 24, but an agreement on oil sanctions proved elusive because so many countries depend on Russian crude.

Russian President Vladimir Putin told Turkish President Recep Tayyip Erdogan that Moscow was ready to work with Ankara to free up Ukrainian ports.

Putin noted the “readiness” of Russia “to contribute to the unimpeded maritime transit of goods in coordination with Turkish partners,” the Kremlin quoted the Russian leader as saying in a readout of a call on May 30 with Erdogan. “This also applies to grain exports from Ukrainian ports.”

Dozens of container ships are blocked in Ukrainian ports that are surrounded by Russian forces, choking off exports of wheat and other commodities from Russia and Ukraine, which together account for about 30 percent of global wheat exports.

Zelenskiy later discussed the situation at the ports, food security, and defense cooperation with Erdogan.

“Unanimously agree on the need to restore peace. We appreciate Turkey’s assistance in this process,” Zelenskiy said on Twitter.