US President Joe Biden and Russian President Vladimir Putin have held phone talks for the second time this month amid mounting tensions over Ukraine.

The two leaders were expected to discuss upcoming bilateral security talks and Russia's meeting with NATO representatives next month. The call was set up at Russia's request.

The United States and European countries have been concerned by Russia's huge deployment of troops near its border with Ukraine.

The Biden administration says it aims to dial down the tensions by talks. But it has also stated its readiness to impose sanctions together with allies if Russia invades Ukraine.

Ahead of the call, Putin also stressed the possibility of resolving the issue through diplomacy.

In a New Year's greeting to Biden, Putin said he was confident they can move forward and establish an effective dialogue based on mutual respect and consideration for each other's national interests.

Russia has demanded a written security guarantee that NATO not expand toward its borders by admitting Ukraine.