US President Joe Biden and his Russian counterpart Vladimir Putin emphasised the need for diplomatic solutions ahead of their latest phone call aimed at defusing tensions surrounding the Ukraine conflict.

The call comes after Moscow earlier this month presented Western capitals with sweeping security demands, saying NATO must not admit new members and seeking to bar the United States from opening new bases in ex-Soviet countries.

The call, which will begin at 2030 GMT, also comes ahead of talks between representatives of the two rivals in Geneva in January, with Washington saying it expects to discuss the Ukraine conflict and Moscow insisting its security demands be contended with.

Biden, who is at his home in Delaware for the New Year’s holiday, will stress in his call with Putin that Washington is looking for a “diplomatic path” out of the crisis, a senior administration official told reporters.

“But we are also prepared to respond if Russia advances with a further invasion of Ukraine,” Biden will tell Putin, the official said, adding that Washington remained “gravely concerned” about the military build-up and wanted to see the Russian forces return “to their regular training areas.”

In a holiday message to Biden hours before the call, Putin said he is “convinced” that “we can move forward and establish an effective Russian-American dialogue based on mutual respect and consideration of each other’s national interests”.

– Conversational mood –

His spokesman Dmitry Peskov then told reporters that Moscow is “in the mood for a conversation”.

“We believe that only through talks is it possible to solve all the immediate problems that we have in abundance between us,” Peskov said, adding that the call was Putin’s initiative.

The call will be the second in less than a month between the two leaders, with Biden in early December warning Putin of “severe consequences” if Russian troops invaded Ukraine.

Washington has led the charge in raising the alarm over Russian troop movements near its ex-Soviet neighbour Ukraine, where the West says Moscow has massed around 100,000 forces ahead of a possible winter invasion.

Putin has denied the allegation and accused the West of stoking tensions, saying that NATO’s eastward expansion is a threat to Russian security.

Ukraine, which has since 2014 fought a pro-Russia insurgency in its east that has claimed over 13,000 lives, has repeatedly said it wants to join the US-led security alliance.

But Russia considers ex-Soviet states to be within its sphere of influence, and has grown increasingly insistent that the only way out of the crisis is the West accepting its demands that would redraw Europe’s security architecture.

At the talks in Geneva next month, Russian Foreign Minister Sergei Lavrov has vowed that Moscow will take a “hard line” aimed at avoiding concessions.

– US support for Ukraine –

His ministry on Thursday said that delegations for the talks will be led by Deputy Foreign Minister Sergei Ryabkov and US Deputy Secretary of State Wendy Sherman.

The United States has called some of the Russian positions non-starters, but said it is willing to talk and will also bring up its own concerns.

Ahead of the US-Russia talks, US Secretary of State Antony Blinken spoke by telephone on Wednesday with Ukrainian President Volodymyr Zelensky.

“I was assured of full US support for Ukraine in countering Russian aggression,” Zelensky tweeted afterward.

Blinken also spoke separately to his counterparts from Britain, France and Germany on “coordination to deter any further Russian aggression against Ukraine”, State Department spokesman Ned Price said.

The Biden administration has vowed to take all actions in lockstep with its European allies.

Following the Geneva talks, Russian delegates will meet with delegates of the NATO alliance ahead of a meeting of the Organization for Security and Co-operation in Europe, a key Cold War forum that brings together Moscow and the West.

“We will determine further steps depending on the readiness of the United States and NATO for substantive talks regarding our concerns,” Russian Foreign Ministry spokeswoman Maria Zakharova told reporters .