Cryptocurrencies tumbled on Sunday in a risk-off move after President Donald Trump hit Canada, Mexico and China with long-threatened import tariffs.

Cryptocurrency prices slid as the spectre of a global trade war put investors on edge and pushed them out of risky assets.

Bitcoin was down more than 4 per cent early on Feb 3 in Asia, touching a three-week low around US$96,606. Smaller cryptocurrency Ether tumbled 12 per cent, back to levels last seen in early November.

A slump in cryptocurrencies weighed heavily on some of the more speculative digital assets late Sunday in the US, a sign investors will slash risk when markets open Monday following new tariffs imposed by Donald Trump.

Renewed trade war, coupled with mass deportations, could add to inflation. BTC's weakness likely reflects those fears.