President Biden and Russian President Vladimir Putin will speak on a call Thursday afternoon amid tensions over Russia’s military buildup on Ukraine’s border. Putin reportedly requested the call, with National Security Council spokesperson Emily Horne telling CNN the leaders plan to “discuss a range of topics, including upcoming diplomatic engagements with Russia.”

There is “some mystery about the reason for Putin’s request to chat,” Politico writes in “Playbook,” though they quoted a New York Times report suggesting that Putin could be “trying to de-escalate a situation largely of his own creation.” But as Politico adds, Putin’s motives might also “be the opposite.”

Biden reportedly plans to emphasize to Putin on the call that in order to make “real progress,” talks must be held in “a context of de-escalation rather than escalation.” Putin seeks a legally binding agreement that Ukraine will not join NATO, which the U.S. and its allies have so far refused.

American and Russian officials plan to hold talks in Geneva on Jan. 10.