Ukraine's military staged air-defence drills on Saturday in the country's east, next to the sea of Azov.
Military jets and helicopters took part in the exercises some 150 kilometres (93 miles) off the rebel-held Donetsk.
Ukraine is set to build a military base on the Azov Sea and has sent more forces to the area to counter a worsening Russian threat, Ukraine's armed forces head told Reuters in October last year, referring to an arm of the Black Sea that is a flashpoint of tensions with Moscow.
Ukraine has been at loggerheads with Russia since the 2014 annexation of Crimea and more than 10,000 people have died in fighting between Ukrainian troops and Moscow-backed separatists. Ukraine and NATO countries accuse Russia of supplying troops and heavy weapons to eastern Ukraine, which Moscow denies.
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