Ukraine said Sunday that a blast triggered by "local resistance movements" in the Moscow-controlled Ukrainian city of Melitopol the previous day killed at least three Russian officers.
Melitopol, with a pre-war population of around 150,000 people, was captured shortly after Russia invaded Ukraine in February last year and now lies behind the front line further north.
"At least three officers of the Russian guard were eliminated" as a result of the "revenge action, carried out by representatives of the local resistance movement," the intelligence service of Ukraine's Defense Ministry said on the Telegram messaging app.
The claims could not be independently verified.
"The attack on the headquarters was carried out during the meeting of the [Russian security service] FSB and [Russian National Guard] Rosgvardia," Ukraine's intelligence service added.
Melitopol is located in Zaporizhzhia, one of the four regions — along with Donetsk, Lugansk, and Kherson — that Russia claims to have annexed despite not fully controlling them.
The exiled mayor of Melitopol Ivan Fedorov on Saturday evening said residents reported an "explosion, which was heard in all corners of the city."
Several Russian-linked officials have been killed in attacks in territories controlled by Moscow's forces since the war began.