Russia has since its 2022 invasion been seeking to take the whole of the Donbas area in eastern Ukraine, where Kyiv's forces have been pushed back towards a line of cities in grinding fighting.
Kyiv has also reported some gains in the deadliest war in Europe since World War Two. Top Ukrainian commander Oleksandr Syrskyi said in mid-April that Kyiv's forces had regained control of nearly 50 sq km of its territory in March.
"Since the beginning of this year, a total of 80 settlements and more than 1,700 square kilometres of territory have come under our control," Valery Gerasimov, Chief of the General Staff of the Russian Armed Forces, said in footage released by the defence ministry on Tuesday.
Reuters was unable to verify the battlefield accounts and the general staff of the Ukrainian armed forces did not immediately respond to a request for comment. Pro-Ukrainian maps indicate Russia has taken 592 square km this year.
Gerasimov said Russia's Southern Grouping of forces was attacking the Donetsk fortress belt comprising the cities of Sloviansk, Kramatorsk and Kostiantynivka, and that Russian forces were about 7 to 12 km (4.3 to 7.5 miles) from Sloviansk and Kramatorsk.
Russian units were already fighting in parts of Kostiantynivka, he said. In addition, Gerasimov said, Russian forces were advancing in Sumy in the north and Kharkiv in the northeast to create what he called "a security zone".
According to Russian estimates, Russia controls about 90% of Donbas, about 75% of the Zaporizhzhia and Kherson regions, and slivers of the Kharkiv, Sumy, Mykolaiv and Dnipropetrovsk regions in Ukraine.
Russia also controls Crimea, which it annexed in 2014 after earlier fighting. The Black Sea peninsula is internationally recognised as part of Ukraine by most countries.
Pro-Ukrainian maps show Russia controls 116,793 square km, or 19.35%, of Ukraine, but that Russia's advance has slowed this year.
(Reporting by Reuters; editing by Andrew Heavens and Timothy Heritage)

A woman reacts near a makeshift memorial dedicated to the fallen Ukrainian soldiers and international volunteers in Independence Square in Kyiv, Ukraine, 20 April 2026, amid the Russian invasion. EPA/SERGEY DOLZHENKO