"Generations of military heroes did not shed their blood on distant shores only to watch our country destroyed by invasion and lawlessness in the Third World," Trump said Tuesday, addressing a group of soldiers at Fort Bragg, North Carolina.
He added, "What you are witnessing in California is a comprehensive assault on peace, public order, and national sovereignty, carried out by rioters waving foreign flags."
Trump ordered the deployment of 700 Marines and 4,000 National Guard members to Los Angeles to quell street protests against his immigration policies.
The US president said the deployment of the military was "necessary to protect federal property and individuals."
Trump warned against continued protests during a military parade in Washington next week to mark the 250th anniversary of the founding of the US military, saying in a White House speech on Tuesday: "For those who want to protest, they will be met with very great force."
On Monday, US Secret Service Agent Matt McCall said that law enforcement agencies are preparing for hundreds of thousands of people to attend the military parade next Saturday.
He added that it has been decided to deploy thousands of officers and specialists from law enforcement agencies across the country.
A Secret Service spokesman said Tuesday that at least nine permits were issued for protests that day.
curfew
This comes as a nighttime curfew imposed by Los Angeles Mayor Karen Bass in downtown Los Angeles went into effect Tuesday evening.
"I have declared a local emergency and imposed a curfew in downtown Los Angeles to stop the vandalism and looting," Bass told reporters.
"Last night, 23 businesses were looted, and I think if you drive around downtown Los Angeles, the graffiti is everywhere and has caused significant damage to businesses and a number of properties," she added.
Since Friday, street demonstrations have erupted in support of detained undocumented immigrants and in condemnation of the Trump administration's immigration policies.
Trump has pledged to deport record numbers of people in the country illegally, close the US-Mexico border, and set a daily target for Immigration and Customs Enforcement to apprehend at least 3,000 migrants.
Neighborhoods of the city are witnessing escalating clashes between protesters and security forces. Video footage shows security forces using tear gas and rubber bullets in an attempt to disperse the demonstrators.
