Russian forces intensify attacks on eastern Ukraine's fortress belt as EU discusses using frozen assets to fund war effort

Russian forces have intensified attacks within Ukraine's so-called "fortress belt" of industrial cities in the eastern Donetsk region, seeking to ramp up pressure on critical Ukrainian strongholds after more than four and a half years of full-scale war.

Russian forces have long targeted the strategic cities of Kostyantynivka, Kramatorsk and Sloviansk as part of a push to completely capture the Donetsk Oblast, one of the Kremlin's key objectives in the conflict.

Speaking at an undisclosed location on Thursday, Russia's Chief of the General Staff Valery Gerasimov said Russian forces had advanced to a position just four kilometers (2.5 miles) from the eastern outskirts of Sloviansk.

Gerasimov also claimed Russian troops had overcome the first defensive line of the Sloviansk-Kramatorsk fortified region in certain areas and that operations were currently advancing along a 160-kilometer front.

The report comes shortly after data from Ukrainian open-source mapping group Deep State found that the most active battlefield actions were taking place around Kostyantynivka, which is seen as the gateway to the rest of the Donbas region.

Analysts at the Washington-based Institute for the Study of War (ISW) said earlier this week that Russian forces had intensified efforts to advance toward Sloviansk from the east and southeast following unsuccessful attempts from the northeast.

In its latest assessment of the Ukraine war, ISW challenged Gerasimov's recent claims of battlefield advances, however, saying they appeared to be designed to construct a narrative of "pervasive" Russian military success and "remain divorced from reality."

Away from the front line, Ukraine's Foreign Minister Andrii Sybiha on Friday welcomed a fresh push from four European Union member states seeking to leverage frozen Russian assets to fund Ukraine's war effort.

"It is only fair and logical to use Russian assets, rather than only European taxpayers money", to cover additional costs of defending Ukraine and the rest of Europe from the Russian threat," Sybiha said in a social media post.

"This discussion needs to be rational, not emotional," he added.

Ministers representing Spain, Sweden, Poland and the Netherlands on Thursday sent a letter to the European Commission, the EU's executive arm, calling on Brussels to restart work on plans to use more than 200 billion euros ($232.9 billion) in Russian central bank assets immobilized under EU sanctions.

Talks on the initiative, which Russia considers "blatantly illegal," collapsed last year when Belgium blocked the move over liability concerns.