Second president of Ukraine and Ukraine's representative in the Contact Group on the peaceful resolution of the conflict in Donbas, Leonid Kuchma, believes Ukrainian party must respond to the active shell attacks of the militants in the east of the country.

"That party violated. Where is the response of the Ukrainian side? We don't have it, we still keeping silent. Why? I don't understand," he told the journalists in Kyiv on Thursday.

Kuchma reminded that on December 22 the agreement on ceasefire was reached in Minsk in late December 23, but the militants broke this agreement.

"We must cry to the whole world that another party violates these agreements, moreover, if this agreement was reached under presence of the Russian representatives. It means that Russia was a guarantor in this regard," he said.