As she noted in her message on Twitter, US Secretary of State Anthony Blinken, Secretary of Defense Lloyd Austin, Chairman of the Joint Chiefs of Staff Mark Milley and National Security Adviser Jake Sullivan reported this to the American leader.
"Secretary Blinken, Secretary Austin, Chairman Milley, and National Security Adviser Jake Sullivan, in a classified call, briefed the President of the United States on an ongoing Russian military attack on Ukraine," the statement said.
Earlier, Russian leader Vladimir Putin, in his address to the citizens of Russia, said that he had decided to conduct a special military operation to protect Donbass.