Biden called Kremlin to give advanced warning he was going to Ukraine

According to the Daily Mail, National Security Advisor Jake Sullivan said that Russia had been warned of BIden’s arrival for "deconfliction purposes."

"We did notify the Russians that President Biden would be traveling to Kyiv. We did so some hours before his departure for deconfliction purposes," Sullivan said.

Sullivan did not give additional details on what the Biden admin said to Russia during the call.

"And because of the sensitive nature of those communications I won't get into how they responded or what the precise nature of our message was, but I can confirm that we provided that notification," he said regarding the call.

Sullivan also refused to reveal Biden’s means of travel to get to Ukraine.

"We will share it, but we just want to make sure we do so once we feel that it's operationally safe to do so," Sullivan said.

Biden reportedly left Washington, DC at 4:15 am on Sunday in secret, flying to Poland before taking a 10-hour train ride to Ukraine.

According to the Daily Mail, one member of the two-person press pool stated that Biden flew to Poland on an Air Force C-32, a plane smaller than the Boeing 747s that would usually be utilized for overseas trips.

The plane flew under the call sign "SAM060" rather than the Air Force One call sign, which stands for Special Air Mission.

The plane stopped in Germany for refueling, after which pilots switched off the plane’s transponder for the hour-long remainder of the flight.

The trip was reportedly supposed to remain secret until Biden left Ukraine’s capital, but plans changed once locals started sharing images online of Biden and Ukraine President Volodymyr Zelensky.

Involved in the planning process were officials from the White House, the chief of staff’s office, the National Security Council, the White House Military Office, the Pentagon, the Secret Service, and the intelligence community.

"Only a handful of people in each of these buildings was involved in the planning for operational security," Deputy National Security Advisor Jonathan Finer told reporters.