People who live near the intersection of 67th and May say police went door to door, telling them they had to leave their homes because military-type explosives were found in a truck on the block.
Police say the vehicle contained rifles, several rounds of ammunition and a grenade.
Several people spent part of the night on a warming bus.
"They say it was dangerous and it may be explosives, but because they are surrounded by the truck and there are all the people around the truck, you know, it was the truck," one woman said.
People were allowed back in their homes after about two hours.