San Francisco police issued an “all-clear” notice Thursday after Union Square was evacuated, triggered by a report of a suspicious package.

However, police later said there was “no merit to the suspicious device,” which was later revealed to be a backpack, adding that streets around the 2.6-acre plaza were reopened.

The backpack was first spotted by a police officer around 11:50 a.m. PST, leading to the evacuation of the square and a one-block radius around it. However, police determined the backpack was “not hazardous,” and an “all clear” was issued slightly more than an hour and a half later.

The square was being set up for this weekend’s Nike Women’s Marathon.

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