"We and the Ukraine armed forces are fully observing the ceasefire regime but unfortunately in response we have received 112 fire attacks in the past 24 hours from the terrorists of Donetsk and Lugansk," Klimkin said during a visit to Sofia.
He added that the attacks were "shellings with mortar artillery and Grad (rockets)."
"Unfortunately the situation remains extremely tense," he said.
The shaky new truce in Ukraine was already at risk Monday as Kiev said there was "no question" of its troops pulling back heavy weapons, as required under a European-mediated truce agreed last week.
"What is necessary now is a stopping of the fire, a withdrawal of the heavy artillery and a start of the exchange of prisoners so that humanitarian aid can get to the people and they receive at least medications and foodstuffs and we can start the political process again.