A U.S. senator said on Wednesday that Russia and President Vladimir Putin could expect sanctions after cyber attacks during the U.S. presidential election in November.

"You can expect that the Congress will investigate the Russian involvement in our elections and there will be bipartisan sanctions coming that will hit Russia hard, particularly Putin as an individual," Republican Senator Lindsey Graham of South Carolina said in the Latvian capital.

Russian officials have denied accusations of interference in the election won by Donald Trump.