- Ukraine started its counteroffensive against Russia in the south.
- UK intelligence said Ukraine pushed Russia back in some places, exploiting "thin" Russian defenses.
Ukraine's counteroffensive is pushing back Russian forces in several places in the south, UK intelligence said.
"Ukrainian armoured forces have continued to assault Russia's Southern Grouping of Forces on several axes across the south of the country since Monday," the UK's Ministry of Defence said on Wednesday.
"Ukrainian formations have pushed the front line back some distance in places, exploiting relatively thinly held Russian defenses."
The front lines between the two adversaries had remained largely unchanged for weeks, which meant that something of a stalemate had been reached.
The UK's new intelligence suggests that Ukraine's offensive, which had been teased for weeks and was announced on Monday, is making progress. Ukraine said on Monday that the counteroffensive had started Kherson and some other areas, but did not give specifics.
Ukrainian President Volodymyr Zelenskyy repeatedly vowed that Ukraine would take back all of its land from Russia, including Crimea, which Russia annexed in 2014.
Zelenskyy and his officials said they would not be sharing many plans about the counteroffensive until after it was complete, citing the need for military secrecy.
Oleksiy Arestovych, a Zelenskyy advisor, said on Monday that Ukraine's operation would deliberately be slow, partly to save lives.
"This is a planned slow operation to grind the enemy, saving the lives of our military and civilians," he wrote.
He said he could understand that people might wish to see a large operation with a fast victory, but that Ukraine's funds are "limited" and so the process will "not be very fast."
The UK defense ministry said that Russia would likely try to plug the gaps in its defenses by bringing in mobile units.
It said Russia was speeding up its efforts to bring in new reinforcements, including with volunteer battalions, but said: "The operational effectiveness of these units is not known."