Demonstrators take to the streets in Washington D.C. on May 29, 2020 to protest over George Floyd’s death. (Photo: Xinhua/VNA)

The US Department of Defense said Sunday that 5,000 National Guard troops in 15 states and the District of Columbia have been deployed to help quell the unrest.

Another 2,000 Guard members are prepared to activate if needed, according to April Cunningham, a National Guard Bureau spokeswoman.

So far nearly 40 cities in the US have imposed curfews after dark to prevent violence and looting by demonstrators in popular shopping districts. Police have used rubber bullets and tear gas to disperse crowds.