The federal building in Oklahoma City was evacuated on Wednesday because of a bomb threat.
Oklahoma City police say a man is in custody after walking into the federal building with a backpack and a note making a bomb threat.
The building and some surrounding buildings have been evacuated.
The federal building in downtown Oklahoma City is near the site of the Alfred P. Murrah Federal Building, which was attacked in a 1995 bombing that killed 168 people.
That was the deadliest act of domestic terrorism on US soil.