A man was arrested trying to clear security at a congressional office building with a gun in his bag Thursday, prompting the U.S. Capitol Police to warn staffers to take safety precautions.

The U.S. Capitol Police sent a security alert just before 8 a.m. ET Thursday telling staff to get inside the nearest office, stay away from external windows, remain quiet and to refrain from entering or exiting the building until given the go-ahead from police.

There was no indication of any other security threat on Capitol Hill besides the one arrested individual.