With Western fears high that Russia is planning to invade Ukraine, tensions spiked on Thursday along the line that separates Ukrainian forces from Russia-backed separatists in the country's east, with both parties accusing each other of intensive shelling.
The Ukrainian military command said shells hit a kindergarten in Stanytsia Luhanska, wounding two teachers, and cutting power to half the town.
Meanwhile, separatist authorities in the rebel-controlled Luhansk region reported an increase in Ukrainian shelling along the tense line of contact in the east.
Ukraine disputed the claim, saying that separatists had shelled its forces, but they didn't fire back.
Eastern Ukraine has been the site of fighting since 2014.
Russia annexed Ukraine's Crimean Peninsula following the ouster of the country's Moscow-friendly president and later threw its weight behind rebels in Ukraine's eastern industrial heartland, triggering a conflict that has killed over 14,000 people.
The head of the monitoring mission for the Organization for Security and Cooperation in Europe, Yasar Halit Cevik, said it reported 500 explosions along the contact line from Wednesday evening to Thursday.
Cevik told the Security Council the tensions then appeared to ease, with about 30 blasts reported.
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