A powerful explosion shook Christmas time on the morning of local time in downtown Nashville, Tennessee, USA.
According to police, it was a deliberate act.
The bomb was placed in a motorhome.
According to Tennessean magazine, no one died in the blast, but three people were taken to hospital.
None of them are in a critical state.
The explosion also damaged about 20 buildings, felled trees and destroyed cars.
The suspected bomb exploded early in the morning local time.
Prior to the explosion, police received an alarm about a shooting and a suspicious motorhome parked next to the telecom operator AT&T's building.
The car sounded a recorded warning that the bomb would explode after 15 minutes.
The recorded female voice counted down on the tape until the bomb exploded.
However, the bomb squad had time to clear the area before the explosion, police spokesman Don Aaron told reporters.
According to police, several people have been taken to the police for questioning, but no arrests have been made.Photo: AFP / Lehtikuva
Buck McCoy, an eyewitness who spoke to CNN, said the entire street was on fire a moment after the explosion.
The windows of his house were broken by the force of the explosion.
A group of bombers isolated the blast site, and several different police agencies are investigating the case.
Police say several people have been taken to police for questioning, but no arrests have been made.
Police have said they will report more about the case on Saturday.
So far, it has not named any motive for setting the bomb and did not mention a possible link to terrorism.
Nashville Mayor John Cooper said the damage caused by the blast is limited to a small area, but any other morning, the consequences would have been more serious.