Police said the stabbing happened around 3.15pm and appears to have happened on a train station platform.
The station, located on G Street NW between 12th and 13th Streets, serves the Red, Orange, Blue, and Silver lines and is one of the system’s busiest transit hubs. It is a few blocks from the White House.
Red Line trains heading to Glenmont bypassed Metro Center station following the incident. Subway employees used megaphones to direct passengers to alternate routes. Metro tweeted shortly before 6 p.m. that these trains were no longer bypassing the station.
DC police tweeted that they were looking for a man carrying a green bag and wearing black shoes, a dark short-sleeved shirt and blue jeans.
Richard Wilson, a 54-year-old man who grew up in the district and works in security at Macy’s across from the station, said: “It’s pretty ridiculous that you can’t even go a day without something crazy to happen.
Manny Rutinel arrived at the Metro Center shortly after the stabbing to catch his train to Shady Grove. He said more mental health services are needed to deter such incidents.
“I’m not too nervous about that stuff, though,” Rutinel said. “There is no alarmist in me.”
Justin George contributed to this report.