“This morning, on almost the entire front line in the Donetsk, Luhansk and Kharkiv regions, the occupiers tried to break through our defenses,” Oleksiy Danilov said in a televised comment. “They started their effort to start the active phase this morning,” he added. The Pentagon did not dispute the Ukrainian reports on Monday, but described the attacks as so-called “reconnaissance operations” in preparation for a larger, future attack. “We continue to see that what we are seeing is a bit of a business formation, that the Russians continue to lay the groundwork for what they believe will be ultimate success on the ground,” Pentagon spokesman John Kirby told reporters. “We believe that the Russians are shaping and setting the stage for future offensive operations. “We are also seeing an active battle in Donbass – as has been the case for the past several weeks.” Russian forces have launched an expected offensive in eastern Ukraine, trying to break through Ukrainian lines in the Donbas region. AFP via Getty Images Donbass, which consists mainly of the Luhansk and Donetsk regions along Ukraine’s eastern border with Russia, has been the site of sporadic clashes since Russia annexed Crimea in 2014 and at the same time supported Moscow in its separatist movements. Donbass. After Russian forces failed to occupy Kyiv last month, the Kremlin announced it was re-focusing its efforts to occupy Donbas while continuing to bomb all of Ukraine. Monday’s reports of fighting in the area come after days of Russian forces gathering near Izyum, a town in the Kharkiv region just outside Donbas. The attack also comes hours after a massive Russian bombardment hit targets across Ukraine, including the western side of Lviv, near the Polish border. Russian authorities say military targets have been hit in Kharkov, Zaporizhia, Dnipro and Mykolaiv, as well as in Donetsk in the heart of Donbass. Donbass has been the scene of sporadic clashes since Russia annexed Crimea in 2014. REUTERS The Pentagon, meanwhile, estimates that Russia has strengthened its forces in southern and eastern Ukraine, adding tens of thousands of troops to the region to at least ten new regular battalion groups. Mariupol, a strategic port in southern Donbass, continued to withstand the Russian attack, although its defenders dwindled. Ukrainian control of the city is the main obstacle to the entry of Russian forces into Crimea in Donbas. Experts have predicted that any full-scale Russian attack on Donbas will take place after the occupation of Mariupol. With Post cables