The North Lawn of the White House was placed on lockdown after someone threw a container over the fence on Monday.
According to WTOP, one person is in custody.
The incident began at around 12:15 p.m., a few minutes after Obama returned from Arlington National Cemetery, according to a report from NBC.
HazMat trucks were seen in the area.
WTOP reported: “An explosive ordnance team was called in to investigate the object, which was described as a container with some papers inside. Tourists were moved away from the fence line on Pennsylvania Avenue back to Lafayette Park.”
The White House was placed on lockdown last week when party balloons drifted over the White House and landed on the North Lawn.
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