U.S. Department of State Spokesperson Heather Nauert has called illegal the supply of goods with humanitarian aid from Russia to Donbas, produced earlier this week by the Russian Emergencies Ministry.

"Russia sent another illegal, uninspected convoy across the border into eastern Ukraine on Monday, likely to resupply its forces," Nauert wrote on Twitter on Friday.

In addition, she accused Russia of "fueling the violence" in Donbas and called on Moscow to "end efforts to destabilize Ukraine."

"Last week Ukraine's Donbas region saw 6,000+ ceasefire violations and 21 Ukrainian soldiers wounded. Russia is fueling the violence; it arms, leads and fights beside anti-government militants. Russia must implement Minsk and end efforts to destabilize Ukraine," Nauert wrote.