Leaders of key Western countries have underlined their support for the sovereignty and territorial integrity of Ukraine and have urged Russia to de-escalate tensions in the region, the White House has said.
The White House said US president Joe Biden had held a call with European allies about the situation in Ukraine ahead of talks with Russian president Vladimir Putin on Tuesday.
The US believes that a build up of tens of thousands of Russian troops on its border with Ukraine could be the prelude to an invasion.
On Monday evening the director of the US Central Intelligence Agency (CIA) Bill Burns warned Americans to be vigilant regarding Mr Putin's designs on Ukraine.
"I would never underestimate president Putin's risk appetite on Ukraine," Mr Burns said during an interview at the Wall Street Journal CEO Council Summit.
“It’s so important to respond to that with a strong mix of deterrence as well as the possibility of diplomacy,” he said.
On Monday, US Senate Republican leader Mitch McConnell said Mr Biden should supply Ukraine with "whatever weapons they think they need" to defend themselves from a potential Russian invasion.
It is expected Mr Biden will warn Mr Putin on Tuesday that Russia would face severe economic consequences should it send troops into Ukraine.
Some US sources have suggested that the Biden administration could target Mr Putin’s inner circle with sanctions but that no decisions had been made.
Other sources suggested sanctions against Russia's biggest banks were also being considered by the United States and its European allies. Another option was going after Russia's ability to convert rubles into dollars and other currencies, the source said.
CNN reported the United States could include the extreme step of disconnecting Russia from the Swift international payment system used by banks around the world.
Bloomberg reported that the US and European allies are weighing sanctions targeting the Russian Direct Investment Fund as well as the country's ability to convert rubles for dollars and other foreign currencies should Russia invade Ukraine.
The US could also restrict the ability of investors to buy Russian debt on the secondary market, Bloomberg added, citing people familiar with the matter.
The White House on Monday said Mr Biden had spoken to the leaders of France, Germany, Italy and Britain ahead of his video call on Tuesday with Mr Putin.
The White House said the Western leaders discussed their “shared concern about the Russian military build-up on Ukraine’s borders and Russia’s increasingly harsh rhetoric”.
It said the leaders of the Western allies had called on Russia to de-escalate tensions "and agreed that diplomacy, especially through the Normandy format, is the only way forward to resolve the conflict in Donbas (region of Ukraine) through the implementation of the Minsk agreements. The leaders underscored their support for Ukraine's sovereignty and territorial integrity. They agreed that their teams will stay in close touch, including in consultation with Nato allies and EU partners, on a co-ordinated and comprehensive approach."
