Several eastbound lanes of New York Avenue at Brentwood Parkway in Northeast Washington were closed about 11:30 a.m. Tuesday as D.C. police investigated a multi-vehicle accident involving at least five children.

Authorities said the injuries and damage did not appear serious, but a mass casualty was declared because of the number of vehicles and people involved.

A D.C. Fire Department spokesman said they were evaluating 11 people, five of them children, but were transporting only one person to an area hospital. Fire officials said four vehicles were involved; police said there were three.

Shortly before noon, police reopened one lane of outbound New York Avenue to traffic, but only for motorists stuck in the initial backup. Authorities were urging people to avoid the area.