Ukraine has gone on the attack and launched a counter-offensive to strike back at Russian forces in the south.

The southern military command announced today they had carried out the long-awaited manoeuvre, reflecting Kyiv's growing confidence as Western military aid flows in. 

Ukrainian public broadcaster Suspilne cited southern command spokesperson Natalia Humeniuk as saying: 'Today we started offensive actions in various directions, including in the Kherson region.'

She confirmed the news minutes later at a briefing.

Ukraine has been talking up a planned counter-offensive in its Russian-occupied southern regions for two months.

Humeniuk said that Ukraine's recent strikes on Russia's southern logistical routes had 'unquestionably weakened the enemy,' adding that more than 10 Russian ammunition dumps had been hit over the last week.

However, she declined to be drawn into giving more details about the new offensive.

'Any military operation needs silence,' she said, adding that Russia's forces in the south are 'rather powerful' and have been built up over a long time.

Russia rapidly captured swathes of Ukraine's south near the Black Sea coast, including Kherson, in the early phase of the war in stark contrast to its failed attempt to capture the capital Kyiv.

Ukraine has been using sophisticated Western-supplied weapons to hit Russian ammunition dumps and wreak havoc with supply lines. Humeniuk told a briefing on Monday that Ukraine had struck more than 10 such ammunition dumps in the past week, adding they had 'unquestionably weakened the enemy'.

She declined to give details of the counter-offensive, saying Russian forces in southern Ukraine remained 'quite powerful'.

The governor of Ukraine's Russian-annexed Crimea Peninsula, Sergei Aksyonov, dismissed the announcement of a counter-offensive on Telegram as 'another fake of Ukrainian propaganda'. Crimea is adjacent to the Kherson region.

The news came as a team from the U.N. nuclear watchdog headed to Ukraine to inspect the Zaporizhzhia nuclear plant - captured by Russian forces in March but still run by Ukrainian staff - that has become a hotspot in the war.

Moscow and Kyiv have traded accusations of shelling in the vicinity of the nuclear plant, Europe's largest and close to frontlines in the war, amid fears of a radiation disaster in a country still haunted by the 1986 Chornobyl disaster.