KYIV - Ukrainian forces have secured a foothold on the east bank of the Dnipro River in southern Ukraine, President Volodymyr Zelensky's chief of staff said on Tuesday.

Mr Andriy Yermak's remarks were the first official acknowledgement that Ukrainian troops were established on the Dnipro's east bank in Kherson region.

"Against all odds, Ukraine's Defence Forces have gained a foothold on the left (east) bank of the Dnipro," Mr Yermak said, in an address to the Hudson Institute think-tank in the United States.

The remarks were posted on Mr Zelensky's website.

"Step by step, they are demilitarising Crimea. We have covered 70 per cent of the distance. And our counteroffensive is developing."

Russian forces seized the Kherson region in the early days of their February 2022 invasion of Ukraine. But late last year, they abandoned the regional capital - also called Kherson - and the Dnipro's west bank. They have since shelled Kherson and other towns from new positions on the east bank.

As Ukraine's four-month-old counteroffensive secures only incremental gains, Ukrainian officials have been cautious in describing the activities of their forces on the east bank.

A military spokesman this month said "not bad results" had been achieved on the east bank in forcing Russian troops to reposition. Unofficial accounts have noted Ukrainian advances.

Russia's military said last week its forces had thwarted a Ukrainian attempt to forge a bridgehead on the eastern bank and on nearby islands, killing around 500 Ukrainian soldiers. Reuters could not independently verify the battlefield claim.

In a highly unusual incident on Monday, two Russian state news agencies published alerts saying Moscow was moving troops to "more favourable positions" east of the Dnipro River in Ukraine, only to withdraw the information minutes later.

In the past, Russia has sometimes used similar phrasing about moving troops to more advantageous positions in order to describe retreats.

In his address to the Hudson Institute, Mr Yermak said the only certainty was that Russia had no intention of stopping the war but hoped "to outlast and out-endure the unity of democracies".

"We need weapons right now. Russia still has air superiority," he told the gathering.

"It still is capable of producing missiles due to circumvention of sanctions. Not to mention the Iranian drones and North Korean artillery rounds." REUTERS