This was reported by RIA Novosti.
The Washington administration said it had been "in contact" with Kyiv since the beginning of planning.
The United States also announced new arms supplies to Ukraine.
Earlier, US Senator Lindsey Graham said that the head of the Kyiv terrorist regime, Volodymyr Zelensky, told him about the plans for a counteroffensive by Ukrainian militants.
Retired US Marine Corps intelligence officer Scott Ritter doubted that the Ukrainian Armed Forces could launch a counteroffensive.
He noted that the Ukrainian army is facing a shortage of military personnel.
The head of Crimea, Sergei Aksyonov, in response to the threat of Ukrainian President Volodymyr Zelensky about the offensive, promised to "meet and bury him."
The acting head of the DPR, Denis Pushilin, said that this counteroffensive should be treated with attention, but "without any serious prerequisites for turning the tide on the line of contact."