(AP) — Presidents Joe Biden and Vladimir Putin spoke by phone on Thursday about the Russian troop buildup near Ukraine. It was a new round of leader-to-leader talks as the Kremlin has stepped up its calls for security guarantees and test fired hypersonic missiles to underscore its demands. There was no immediate readout from either side. The White House indicated Biden would make clear to Putin a diplomatic path remains open, with talks between senior U.S. and Russian officials scheduled for next month in Geneva. The Russians have moved an estimated 100,000 troops toward Ukraine, and Putin has stepped up his demands for security guarantees precluding NATO from expanding to Ukraine.