Secret Service spokesman George Ogilvie told Politico the suspect in custody was Alexander Sahagian.
Sahagian, 52, had not been charged.
Politico said the Secret Service was seen handcuffing a white man with dark hair and wearing a blue shirt with light-colored shorts.
The incident, which occurred about 6:30 p.m. EDT just a few miles from the Washington Navy Yard where a deadly shooting spree took place earlier in the day, prompted police to shut down 2 blocks of 17th Street NW and a block of Pennsylvania Avenue on the northwest side of the White House.
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