The US and EU have condemned President Vladimir Putin’s first visit to Crimea since Russia annexed the peninsula from Ukraine in March.
The US state department said the trip was “provocative and unnecessary”. The Kiev government called it a “gross violation of Ukraine’s sovereignty”.
Putin praised Crimea for joining Russia, as he marked the Soviet victory over the Nazis in World War Two.
As he visited, there were deadly new clashes in south-eastern Ukraine.
Ukraine’s Interior Minister Arsen Avakov said at least 20 pro-Russian activists and a Ukrainian security officer died in the clashes in the port of Mariupol.
The government said there was a gun battle when pro-Russian activists tried to storm a police HQ.
However, some local witnesses accused the security forces of opening fire on unarmed protesters who had entered the building. Local officials put the casualties at seven dead and 39 injured.
Crimea voted to join Russia in March – in a referendum dismissed by Kiev and the West as illegal.
Pro-Russian separatists in Ukraine’s eastern Donetsk and Luhansk regions are planning to hold secession referendums on Sunday.
The separatists remain in control of many official buildings across the east despite a military operation by Kiev to remove them. Dozens have been killed in the unrest.
US State Department spokeswoman Jen Psaki called Mr Putin’s trip provocative and unnecessary, adding: “Crimea belongs to Ukraine and we don’t recognise of course the illegal and illegitimate steps by Russia in that regard.”
US National Security Council spokeswoman Laura Magnuson said the visit “only served to fuel tension”.
Maja Kocijancic, a spokeswoman for EU foreign policy chief Catherine Ashton, said the EU “regretted” the presence of Putin at a military parade in Crimea’s port of Sevastopol. BBC