Russia's progress made through May on the southern Popasna axis has stalled over the last week, Britain's defence ministry said on Tuesday.
Reports of heavy shelling near Izium suggests Russia is preparing to make a renewed effort on the northern axis, it also said in a tweet.
"Russia will almost certainly need to achieve a breakthrough on at least one of these axes to translate tactical gains to operational level success and progress towards its political objective of controlling all of Donetsk Oblast," the ministry said.
Reuters could not immediately verify the ministry's report.
(Reporting by Jahnavi Nidumolu in Bengaluru; Editing by Tom Hogue)
