Russian forces have made no headway along the front lines, but are entrenched in heavily mined areas they control, making it difficult for Ukrainian troops to move east and south, Ukrainian officials said on Wednesday.
Russian accounts of the fighting on the frontline said 12 Ukrainian attacks had been repelled in Donetsk region - a focal point of Russian advances for months.
Much of Russian military activity focused on air attacks that damaged grain infrastructure in Ukraine's Danube port of Izmail. Russia's Defence Ministry also said its forces had destroyed a Ukrainian naval drone that tried to attack a Russian warship escorting a civilian vessel in the Black Sea.
Ukrainian forces launched a drive in June to retake occupied areas and have been pressing southward toward the Sea of Azov to sever a land bridge between occupied eastern Ukraine and the Russian-annexed Crimean peninsula.
Kyiv also says it has retaken areas near Bakhmut, an eastern city seized by Russian forces in May after months of battles.
Deputy Ukrainian Defence Minister Hanna Maliar said Russian forces had "tried quite persistently to halt our advance in the Bakhmut sector. Without success."
Russian forces, she wrote on the Telegram messaging app, were beefing up reserves and equipment in three areas further north, where heavy fighting has also been reported in recent weeks.
Oleksiy Danilov, the Secretary of Ukraine's Security Council, said Russian forces had ample time in months of occupation to prepare defences and lay extensive minefields.
"The enemy has prepared very thoroughly for these events," he told national television. "The number of mines on the territory that our troops have retaken is utterly mad. On average, there are three, four, five mines per square metre."Danilov restated assertions by President Volodymyr Zeleskiy that the advances, while slower than hoped, could not be rushed as human lives were at stake.
"No one can set deadlines for us, except ourselves... there is no fixed schedule," he said. "I have never used the term counter-offensive. There are military operations and they are complex difficult and depend on many factors."
Russia's Defence Minister, in its account of the fighting,
said Ukrainian forces had made unsuccessful attempts to advance in several sectors in both southern and northern parts of Donetsk region.
It also said Russian forces had launched strikes on towns around Bakhmut, including Kurdyumovka on the city's southern fringes and Chasiv Yar, the first major town to the west.
(Reporting by Ron Popeski. Editing by Gerry Doyle)
