Erdogan supporters and security guards clashed with Kurdish and Armenian protesters who accuse him of human rights abuses – leaving nine in hospital with one in a critical condition.
Two people were arrested as Erdogan and Trump attempted to improve relations between their countries.
The Turkish president stopped by the ambassador’s residence in the upscale Sheridan Circle neighbourhood, where protests prompted city officials to shut down nearby streets.
Yazidi Kurd demonstrator Lucy Usoyan told ABC: “All of the sudden they just ran towards us.
“Someone was beating me in the head non-stop, and I thought, ‘OK, I’m on the ground already, what is the purpose to beat me?’”
Washington police eventually sent reinforcements and restored order, but emergency services said nine people were taken to the hospital, one of them in critical condition.