Moscow, June 5 : The Russian Defence Ministry has claimed of thwarting a major offensive by Ukraine in the separatist Donetsk region which led to the deaths of some 250 Ukrainian troops. Neither the Ministry's claim has been independently verified nor has the Ukrainian government commented on the development, the BBC reported on Monday. In a statement on the social media platform Telegram, the Ministry said that "on the morning of 4 June (Sunday), the enemy launched a large-scale offensive in five sectors of the front in the South Donetsk direction" using six mechanised and two tank battalions. It further said the Ukrainians tried to break through Russian defences, but the "enemy did not achieve its tasks, it had no success". A video posted on the platform showed military vehicles being attacked from the air. Besides the 250 troops, the Russian Ministry also claimed that Ukraine lost at least 16 tanks on Sunday. For months now, Ukraine has been planning a counter-offensive for months. But officials in Kiev have warned against public speculation over the measure, saying it could help the enemy. "Plans love silence. There will be no announcement of the start," the Ukrainian Defence Ministry said in a video on Sunday. The footage featured masked and well-armed troops holding their fingers against their lips. /IANS