Local police are advising people to take care following the discovery of an old World War II hand grenade in Carew on Saturday afternoon.
The grenade was detonated in a controlled explosion by a bomb disposal team from Hereford after being unearthed by workmen constructing the new Sageston/Redberth bypass.
However, the police are 'greatly concerned' that the grenade had been moved to a shed to await the bomb disposal experts' arrival.
"The grenade was very old and rusty and was very unstable," said a police spokesman.
"Bearing in mind that much of the construction work for the bypass is on a former military site, there is a likelihood that there could be other bits of military ordnance out there.
"If anyone finds anything, the advice is not to touch it, mark where it is and call out the police immediately."