(Updates with more details, residents on helicopters)
MOSCOW, April 24 (Reuters) - Russia started military drills near the border with Ukraine on Thursday in response to operations by Ukrainian forces against pro-Russian separatists and NATO exercises in eastern Europe, Defence Minister Sergei Shoigu was quoted as saying.
"The go-ahead has already been given (by the Kiev) authorities for the use of force against civilians," the Interfax news agency quoted Shoigu as saying.
"If this military machine is not stopped, it will lead to greater numbers of dead and wounded. Planned exercises by NATO forces in Poland and the Baltic countries do not foster normalisation of the situation surrounding Ukraine, either.... "We are forced to react to such a development of the situation."
The minister said that starting on Thursday, battalions of tactical groups from the armed forces' southern and western military districts would begin exercises in regions of Russia bordering Ukraine.
"Apart from that, the air force will conduct flights to train for manoeuvres along the state borders," Interfax quoted Shoigu as saying.
Two local residents in areas near the Ukrainian border told Reuters on Thursday they had spotted formations of attack helicopters in the air.
A witness who was near the city of Belgorod, in a location about 25 km from the border, said she saw 10 helicopters heading in the direction of the eastern Ukrainian city of Kharkiv. It was not clear if they crossed the border.
A second witness, near the village of Valuyki, in Belgorod region, said he saw 10 helicopters heading away from the border. (Writing by Steve Gutterman and Christian Lowe, editing by Nigel Stephenson)