Witnesses reel after Ukraine kindergarten shelling

Kindergarten worker Natalia Slesareva's ears were ringing after she was thrown against a door by a shell blast during an attack that has sent tensions soaring, amid fears that Russia will invade Ukraine.

The projectile blew a hole in the wall of a two-storey building being used by 20 children and 18 staff in the government-held eastern Ukrainian village of Stanytsia-Luhanska.

It was a close call.

Everyone escaped relatively unharmed after rushing to the other side of the building and cowering against the walls on the ground floor.

"The children were eating breakfast when it hit," Slesareva said. "It hit the gym. After breakfast, the children had gym class. So another 15 minutes, and everything could have been much, much worse."

Both Kyiv and the Russian-backed rebels fighting each other across Ukraine's southeast for the past eight years accused the other side of launching a dangerous wave of new attacks across the front.

Slesareva was still trying to make sense of what happened as she examined the piles of brick scattered across the damaged gym room.

"I was at my usual place at work, in the laundry room," the 58-year-old laundress said. "The explosion wave blew me back against the door. Then -- smoke, dust, broken windows."

"I could not feel the right side of my head. Everything was ringing."

A series of Ukrainian and Western leaders have expressed alarm and urged Russia not to exploit the tensions on the front line as a pretext to launch its feared offensive against Ukraine.

More than 100,000 Russian troops have all but encircled Ukraine during the Kremlin's standoff with the West over NATO's expansion into eastern Europe.