“They discussed the ongoing unprovoked Russian invasion of Ukraine and exchanged views and assessments.
The chairman reaffirmed his strong support for the sovereignty and territorial integrity of Ukraine," TASS quoted the message as saying.
The American military leader called Ukraine a key partner for NATO.
Earlier, President of Ukraine Volodymyr Zelensky said that NATO countries should launch preemptive strikes against Russia to prevent Moscow from using nuclear weapons.
The press secretary of the Russian president, Dmitry Peskov, called Zelensky's words a call for a world war.
The Kremlin has repeatedly noted that Russia can use nuclear weapons only in accordance with the provisions of its nuclear doctrine.