President Biden and Russian President Vladimir Putin spoke one-on-one Tuesday morning regarding tensions between the Kremlin and Ukraine, a “high-stakes diplomatic effort” by the U.S. at deterring Russia from invading Kyiv. Though exact details of the meeting have yet to emerge (if they do at all), here’s what we know about what went down:

As for the conference’s kick off, CBS News’ Ed O’Keefe shared a video broadcast from Russian state television showing Biden and Putin kindly greeting one another as the bilat began.

Just don’t think the two leaders were waving hi to one another over Zoom, reports The New York Times. Instead, Biden relied on his administration’s “secure communications process” to get through to Russia, a system with protocol that often varies from White House to White House. A secure call essentially means the resulting conversation is encrypted.

Biden appeared alone on screen in the White House’s Situation Room, but it is “common practice” to have aides listening in nearby, with a note taker present also present to piece to together an accurate account of the call. In this case, reports the Times, a translator would likely be in attendance, as well.

All in all, the two leaders spoke for two hours and one minute, according to the White House. An official readout of the meeting says Biden used the bilat to voice “deep concerns” about Putin’s escalation of forces around Ukraine, and make “clear that the U.S. and our allies would respond with strong economic and other measures in the event of military escalation.” The presidents also discussed strategic stability, ransomware, and “joint work on regional issues such as Iran.”