A Florida man has disappeared into a 20ft-deep (6m) sinkhole that swallowed up a bedroom in his house.
Jeffrey Bush, 36, is presumed dead after rescue crews failed to make contact with him.
Officials in the town near Tampa have postponed further rescue efforts until they determine how much of the ground under the house is compromised.
Sinkholes are common in certain parts of Florida, Hillsborough County's fire chief said.
"Florida essentially sits on a system of caverns," Chief Ron Rogers said, saying water erosion in the caverns causes them to collapse and sinkholes to form on the surface.
The sinkhole is currently 30ft wide and 20ft deep, but officials have established a 100ft-wide safety zone, fearing the top of the sinkhole is growing.
"We don't know how stable the house is," Chief Rogers said, adding that additional parts of the home began to collapse into the ground while rescuers were inside.
Jeffrey Bush's brother Jeremy told rescue crews he heard a loud crash near midnight on Thursday, then his brother screaming for help.
He said he jumped into the hole but couldn't see his brother.
"The floor was still giving in and the dirt was still going down, but I didn't care. I wanted to save my brother,'' he said, choking back tears outside a neighbour's house.
"I could swear I heard him hollering my name to help him.''
One of the first responders to the house had to pull Jeremy Bush back from digging through the widening hole.
"All they could see was a part of a mattress sticking out of the hole," Chief Rogers said. "Essentially the floor of that room had opened up."
There has been no contact with Jeffrey Bush since then, although officials said they had inserted cameras and listening kit into the hole.
Neighbours on both sides of the home have been evacuated.