'Serious' talk between Biden and Putin sets stage for diplomacy

US President Joe Biden and his Russian counterpart Vladimir Putin on Thursday exchanged warnings over Ukraine but conveyed some optimism that upcoming diplomatic talks in January could help ease spiralling tensions.

In a 50-minute call, their second conversation this month, Biden said he needed to see Russia de-escalate its military build-up near Ukraine, while Putin said sanctions threatened by Washington and allies could lead to a rupture in ties. The call was requested by Putin.

"President Biden reiterated that substantive progress in these dialogues can occur only in an environment of de-escalation rather than...