Thai police found and defused a bomb on Monday, a week after an explosion killed 20 people in the country's worst-ever bomb attack, but it was not clear if the device found at a Bangkok construction site had anything to do with the earlier blast.

The discovery of the bomb came after police said the trail had gone cold in the hunt for those responsible for the Aug. 17 attack on Bangkok's most famous shrine, and they were unsure if the main suspect was still in the country.

"We received reports this afternoon of a bomb in Sukhumvit 81," Kamthorn Aucharoen, commander of the police's explosive ordnance team, said, referring to a road off of one of Bangkok's main thoroughfares.