Ukrainian forces have made some breakthroughs in the southern Kherson region and taken control of some settlements, a Russian-installed official said on Monday.

"It's tense, let's put it that way," Vladimir Saldo, the Russian-installed head of Ukraine's Kherson region, said on state television.

Russia formally moved to annex four Ukrainian territories last week, including Kherson region, but none are fully under the control of Moscow's forces and Ukraine continues to advance in the south.

(Writing by Caleb Davis)