"If the protests are not quelled in two days, I will send the National Guard to clean Portland of this terrorist hive," Trump tweeted.
Portland has become the protest's epicenter in the U.S. after several videos and testimonies posted on social networks showed how federal agents were repressing protesters.
The agents, who drive around the city in unmarked vehicles, have used tear gas and stun guns against protesters. They have also been seen surrounding citizens and arresting them without apparent justification.
"The Federal agents will not leave town until the demonstrations are quelled. If they need reinforcements, they will get them," Trump added.