According to Kerry, all Minsk deal conditions, including the withdrawal of heavy weapons, allowing the Organization for Security and Co-operation in Europe (OSCE) to monitor the region, and Kiev's grant of special status to Donbas, must be implemented before sanctions can be lifted and US-Russia relations can be fully restored.
Russia has repeatedly refuted the accusations of direct military involvement and participated in negotiating the Minsk agreements for a peaceful resolution to the conflict in Ukraine.
The Minsk agreements, a set of measures hammered out by leaders of Russia, Ukraine, France and Germany, are intended to facilitate the process of Ukrainian reconciliation. The deal was signed by Kiev and eastern Ukrainian militia in February 2015.