Fighting has become more heated along the front line in eastern Ukraine, with Russia exploiting its advantage over Kyiv’s forces along several axes, Ukraine’s top soldier said.

“In an attempt to seize the strategic initiative and break through the front line, the enemy has concentrated its main efforts on a number of directions,” army commander-in-chief Oleksandr Syrskyi said Sunday in a long post on Telegram and Facebook.

This happened as Russia has “created a significant advantage in forces and capabilities,” he added. “The situation on the front has escalated.”

Kremlin forces have been attacking along the whole length of the front line, posting “tactical successes” in some areas, while Ukraine is still able to achieve some local gains in others, Syrskyi said. He described the situation is “dynamic,” with some positions changing hands several times per day.

The assessment comes as Ukraine expects the arrival of the long-expected batch of U.S. military materiel. It also confirms recent warnings from U.S. and U.K. officials that Vladimir Putin’s troops have looked to press their advantage while Kyiv’s forces are underequipped and short on manpower.

Syrskyi listed half a dozen areas where Russia is pushing forward with increased pressure. The most difficult situation is west of the Russia-held city of Donetsk, where Moscow’s troops forced Ukrainians to give up some positions near the towns of Kurakhove and Pokrovsk.

Russian forces expanded their control farther north from Donetsk by capturing the town of Novobakhmutivka, the defense ministry in Moscow reported on Sunday. Ukraine hasn’t commented on the town’s status.

Moscow’s troops also had some limited success near an important logistics hub of Kupyansk in the north-east, according to Syrskyi, as well as north of Bakhmut. Putin’s commanders are eyeing a potential offensive move toward Slovyansk, the Ukraine-held city that was a scene of heavy fighting as far back as 2014.

Ukrainian forces were able to improve their positions near Kupyansk and Lyman as well as liberate another island in the sprawling Dnipro River delta near Kherson, Syrskyi said.

Military commanders are also monitoring the Russian buildup of forces near Kharkiv, not far from the border in Ukraine’s northeast, even as Kyiv sees no immediate threat of a major offensive in the north.

“Russian forces will likely make significant tactical gains in the coming weeks as Ukraine waits for U.S. security assistance to arrive at the front, but remain unlikely to overwhelm Ukrainian defenses,” the U.S.-based Institute for the Study of War wrote in an overnight update.

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