The situation on the front line in eastern Ukraine is worsening but local defenders are so far holding firm against a concerted push by Russia’s bigger and better-equipped forces, a senior Ukrainian military official said Thursday.

Russia has amassed troops in the Donetsk region in an effort to punch through the Ukrainian defensive line, according to Nazar Voloshyn, spokesperson for Ukrainian strategic command in the east of the country.

“The enemy is trying to seize the strategic initiative and breach our defense,” Voloshyn said on national television.

“The enemy is actively attacking along the entire front line, and in several directions they have achieved certain tactical advances,” he said. “The situation is changing dynamically.”

Russia has pushed Ukraine onto the back foot on the battlefield as Kyiv grapples with shortages of troops and ammunition. Ukrainian forces are now racing to build more defensive fortifications at places along the around 1,000-kilometer (600-mile) front line.

Ukraine’s difficulties have been deepening for months as the military waited for vital new military aid from the United States. The support was held up in Washington for six months.

Ukrainian soldiers withdrew from Avdiivka, a city in the Donetsk region, in February under a withering Russian barrage that had sapped their fighting strength and morale. Since then, the Kremlin’s forces have used their military might to take village after village in the area, bludgeoning them into submission, as they look to capture the parts of Donetsk they don’t already occupy.

Cities in Russia’s crosshairs, including recent target Chasiv Yar in eastern Ukraine, are pulverized by Moscow’s missiles, drones and glide bombs.

The Donetsk and Luhansk provinces together make up the Donbas, an expansive industrial region bordering Russia that President Vladimir Putin identified as a focus from the war’s outset and where Moscow-backed separatists have fought since 2014.

Also, Russia launched its third attack in a week on Odesa, firing ballistic missiles at the southern Ukrainian port city and injuring 14 people, local officials and emergency services said.

The attack hit a sorting depot belonging to Ukraine’s biggest private delivery company, Nova Poshta. No staff were injured, the company said, but the strike started a major fire.

On Monday, six people were killed in a Russian missile strike on Odesa, and two days later three people died there when the Kremlin’s forces targeted civilian infrastructure.

Long-range strikes have been a feature of Europe’s biggest conflict since World War II, which mostly has focused on attrition. Kyiv officials have pleaded for more air defense systems from Ukraine’s Western partners, but they have been slow in coming.

Ukrainian President Volodymyr Zelenskyy said Thursday that Russia had launched more than 300 missiles of various types, almost 300 Shahed-drones, and more than 3,200 guided aerial bombs at Ukraine in April alone.

Odesa, a key export hub for millions of tons of Ukrainian grain exports through the Black Sea, has been repeatedly targeted by Russia. Thursday was the 10th anniversary of clashes in the city between pro- and anti-Russia demonstrators that left 48 people dead.

Ukraine has deployed increasingly sophisticated long-range drones to hit back, aiming at targets on Russian soil, especially infrastructure that sustains the Russian economy and war effort.

The governors of three Russian regions reported that energy facilities were damaged by Ukrainian drone strikes overnight. Oryol region Gov. Andrei Klychkov said energy infrastructure was hit in two communities. The Smolensk and Kursk governors reported one facility damaged in each region.

The Russian Defense Ministry said Ukrainian drones were shot down over the Bryansk, Krasnodar, Rostov and Belgorod regions. Most were intercepted in Bryansk, where five were brought down, it said.

(AP)