The tweet comes as chaos has erupted across the United States over the last few days following the death of George Floyd.
Mr Trump said: “The United States of America will be designating ANTIFA as a Terrorist Organization.
“The Lamestream Media is doing everything within their power to foment hatred and anarchy.
“As long as everybody understands what they are doing, that they are fake news and truly bad people with a sick agenda, we can easily work through them to greatness!”
At least 30 large demonstrations have taken places across cities in the US while the National Guard were also deployed to Minnesota.
Mr Trump also criticised the mayor of Minneapolis for failing to control the protests.
He also declared the protestors as “looters and anarchists” while accusing them of dishonouring the memory of Mr Floyd.