US President Joe Biden said Tuesday that the United States would continue to supply "defensive" weapons to Ukraine against a Russian invasion and deploy more US troops to reinforce NATO allies in Eastern Europe.

"I have authorised additional movements of US forces and equipment, already stationed in Europe, to strengthen our Baltic allies, Estonia, Latvia and Lithuania," Biden said.

"Let me be clear, these are totally defensive moves on our part," he said while accusing Russia of being the aggressor. He said the US did not intend to fight Russia, but warned that it would defend every inch of Nato territory. 

The President also announced a first tranche of sanctions against Russia after it said it was recognising two separatist republics in Ukraine. As in the case of the EU, the sanctions target Russian banks 'to starve the country of financing.' 

"We're implementing sanctions on Russia's sovereign debt. That means we've cut off Russia's government from Western financing," Biden said.

The measures also would target financial institutions, and Russian "elites," the US leader said.