'Casualties' in Ukraine gun battles

A Ukrainian officer has been killed in a gun battle with pro-Russian armed men in the eastern city of Sloviansk, the interior minister says.
Both sides suffered a number of casualties, Arsen Avakov said.
Pro-Russian forces took over Sloviansk on Saturday and have targeted at least four other cities, prompting Kiev to launch an "anti-terror operation".
Kiev and Western powers accuse Moscow of inciting the trouble. The Kremlin denies the charge.
US officials said on Saturday there had been a "concerted campaign" by forces with Russian support to undermine the authorities in Kiev.
Secretary of State John Kerry warned of "additional consequences" if Russia failed to make efforts to "de-escalate" and pull its troops back from Ukraine's border.
But Russia's Foreign Minister Sergei Lavrov said the Kiev government was "demonstrating its inability to take responsibility for the fate of the country".
He had warned earlier that any use of force in eastern Ukraine could scupper crisis talks due later this week.
Ukrainian officials were due to meet counterparts from Russia, the US and the EU in Geneva on Thursday.
'Shooting to kill'
On Saturday, armed men took over police stations and official buildings in Sloviansk, Kramatorsk and Druzhkovka.
Unconfirmed reports suggested official buildings had also been taken over in two other cities - Mariupol and Yenakievo.
Similar accounts emerged from Sloviansk and Kramatorsk on Saturday of armed men dressed in camouflage arriving in buses and storming the police stations.
Pro-Russian demonstrators also continued their occupation of the main administrative building in the regional capital Donetsk, which they have held for one week.
A protest leader told the BBC that the activists in Sloviansk took action to support the Donetsk sit-in.
BBC reporters in Sloviansk said the gunmen were well-organised and quickly established control throughout the town.
Checkpoints had been set up on the main roads into the town.
Avakov labelled the actions a "display of aggression by Russia".