Kirby said this in an interview with MSNBC when asked what to expect from an "embarrassed and furious" Putin after Ukrainian troops seized a large number of settlements in the Kursk region, Ukrinform reports.
"We have seen the Russians react to it [Ukraine's military operation] in terms of diverting some military manpower and resources to the Kursk area," he said.
Read also: U.S. reluctant to allow Ukraine to use ATACMS inside Kursk region - CNNKirby noted that it is not clear exactly how many forces the Russians are going to put there, "what their intentions are, what they are going to do, or what the Ukrainians are doing."
According to Kirby, the U.S. is talking to the Ukrainians "in real time."
"We want to better understand what is going on here. In the meantime, we will continue to make sure that Ukraine has the weapons and capabilities it needs to defend itself," he said, adding that new military aid packages will be announced in coming weeks.
Earlier reports said that the Ukrainian Armed Forces had taken control of more than 1,000 square kilometers of territory in the Kursk region with dozens of settlements.