Russia has said Ukraine fired US-supplied long-range missiles into the country for the first time on Tuesday.
Ukraine used Atacms missiles in a strike on Russia's Bryansk region this morning, the ministry of defence in Moscow said.
Five missiles were shot down and one damaged, with its fragments causing a fire at a military facility in the region, it said in a statement.
Use of the US missiles was also reported in Ukrainian media, but Ukraine has not yet commented.
This breaking news story is being updated and more details will be published shortly. Please refresh the page for the fullest version.
You can receive Breaking News on a smartphone or tablet via the BBC News App. You can also follow @BBCBreaking on Twitter to get the latest alerts.