This was confirmed by observers from the Organisation for Security and Co-operation in Europe. They reported seeing a convoy of 43 unmarked military trucks travelling into the rebel stronghold of Donetsk. After and despite a two-month ceasefire, such a military development is considered dangerous by the international community. Ukraine Defence Minister Stepan Poltorak said Kiev was preparing for a possible new round of fighting. The reaction was strong in the U.S.: “We and our allies and partners would be prepared to broaden and deepening existing sanctions,” State Department spokeswoman Jen Psaki said. As always when they had to give explanations, Russian officials denied the claims and marked them as “unfounded.” Nato chief Jens Stoltenberg has urged Russia to pull back its forces.