MOSCOW, June 9 (Reuters) - Russia's foreign ministry said on Friday that it had summoned the Japanese ambassador over Tokyo's decision to supply military equipment to Ukraine.

Japan - which has backed Western sanctions against its long-time antagonist in East Asia in response to Moscow's military campaign in Ukraine - last month promised Ukraine around 100 military-use vehicles having previously given protective equipment such as helmets and bullet-proof vests.

However, Moscow said Tokyo was supplying armoured vehicles as well as all-terrain vehicles.

"The Japanese side was told that this step would lead to an escalation of hostilities and a further increase in the number of human casualties of the Kyiv regime," the ministry said in a statement.

Japan's export rules ban its companies from selling lethal items overseas.

The Japanese Embassy said the ambassador, Toyohisa Kozuki, had told Deputy Foreign Minister Andrei Rudenko that Moscow's attempts to deflect blame for the consequences of the conflict were "completely unreasonable and absolutely unacceptable".

"Russia's aggression against Ukraine, as an attempt to unilaterally change the status quo by force, is a clear violation of international law and is absolutely unacceptable," he was quoted as saying.