Russia says Ukraine struck homes

a helicopter
Russia says Ukraine has injured 7 people in strikes across the border in the Bryansk region -AP

Russian officials said Ukrainian helicopters have hit residential buildings and injured seven people in the Bryansk region, the latest of a series of cross-border attacks that Moscow has said may trigger a retaliatory attack on Kyiv.

The governor of the Belgorod region said a village there was also attacked, but that no one was injured.

Ukraine's defence ministry, which has declined to comment on several border incidents including a strike on a fuel depot in the city of Belgorod earlier this month, did not immediately respond to a request for comment about the latest development.

The Ukrainian government's Centre for Countering Disinformation issued a statement accusing Russia's intelligence services of implementing "a plan to carry out terrorist acts to whip up anti-Ukrainian hysteria" in Russia.

The statement mentioned two alleged attacks in the western Russian city of Bryansk but not the alleged air strike.

"On April 14, 2022, using two combat helicopters equipped with heavy offensive weapons, military personnel of the Armed Forces of Ukraine illegally entered the airspace of the Russian Federation," Russia's investigative committee said in a statement.

"Moving at low altitude, they carried out at least six air strikes on residential buildings in the village of Klimovo," it said. Six buildings were damaged and seven people were injured, the statement said.

A health ministry official said two people had been seriously injured, RIA news agency reported.

Bryansk regional authorities closed schools for fear of further strikes, TASS news agency reported.

Vehicles were damaged when a border post came under mortar fire from Ukraine near Klimovo on Wednesday, Russia's FSB security service told state television.

Russia's defence ministry said on Wednesday the continuation of "sabotage and attacks" by Ukrainian forces could trigger strikes on Kyiv.

"If such incidents continue, then consequence from the armed forces of the Russian Federation will be attacks on decision making centres, including in Kyiv, which the Russian army has refrained from to date," the defence ministry said.

Authorities in four Russian regions bordering Ukraine and in Russian-controlled Crimea announced they were stepping up security measures on Monday over what they said were "possible provocations" from the Ukrainian side.

Moscow's invasion of Ukraine, the biggest attack on a European state since 1945, has seen more than 4.6 million people flee abroad, killed or wounded thousands and left Russia increasingly isolated on the world stage.

The Kremlin says it launched a "special military operation" in late February to demilitarise and "denazify" Ukraine. Kyiv and its Western allies reject that as a false pretext for an unprovoked attack.