Russia has made a rare admission, saying that a key air defence system and an air base in the Kursk region were hit by Ukraine with US-supplied Atacms missiles.
The defence ministry statement, which threatened retaliation, came a day after Ukraine said it had hit targets in the region.
Meanwhile Ukraine’s air force said Russia launched a record 188 drones in a single attack on Monday night, damaging critical infrastructure.
Tensions have been high since the US reportedly allowed Ukraine to use Atacms missiles on targets inside Russia last week, in response to Russia deploying North Korean troops.
The week culminated with Russia’s use of the powerful new intermediate-range Oreshnik ballistic missile on the Ukrainian city of Dnipro.
The first reported strikes by Atacms on Russian territory were reported on Tuesday, when Russia said falling fragments caused a fire at a military facility.
But Monday’s strike on an S-400 air-defence missile battalion at Lotarevka northwest of Kursk on Saturday could be seen as more serious. The S-400 is considered the closest Russian equivalent of the US Patriot missile system.
The Defence Ministry said three of the five Atacms missiles were shot down but two reached the target, damaging a radar system and causing casualties.
It also said a second strike on Monday on the Khalino (Kursk East) air base caused “insignificant damage” after one of the eight missiles fired by Ukraine got through air defences.
“The Ministry of Defence of the Russian Federation is in control of the situation and retaliatory measures are being prepared,” the statement added.
It shared photos of what it said was debris from the air base attack.
Russian military bloggers reported the Khalino attack on Monday.
Also footage posted to social media on Monday – which documented bright flashes in the sky above the border region – claimed to show the moment Atacms missiles were intercepted by Russian air defences elsewhere in the Kursk region.
BBC Verify corroborated that the footage was genuine and filmed in Kursk city, but could not establish whether the US-supplied missiles were the source of the flashes.
A record 188 drones and four Iskander missiles attacked Ukraine overnight, the country’s air force said on Tuesday.
It said 76 of them had been shot down while another 95 had been “lost track of”, and that critical infrastructure and residential buildings had been hit.
Some 70% of the power of the western Ternopil region was cut, its governor said.
Meanwhile the exiled Russian investigative news website Agentstvo has claimed that Ukraine is now losing territory at the fastest rate since the early days of the full-scale invasion.
However, Russian gains in eastern Ukraine are still extremely slow compared to the rapid advances of February and March 2022, when its forces came close to the capital Kyiv.
