Swansea Council is investigating a noise after complaints it kept people awake until the early hours in the Port Tennant area of the city.
Liam Williams, 27, who lives in the area, took to Facebook this morning to report the noise nuisance and ask if anyone else had heard it.
He wrote: "Anyone know what that alarm is going off near Port Tennant? Been going for the past few hours now and it’s doing our head in."
He added: "I read it was a broken alarm down the docks. We first started hearing it around 9pm last night and it was still going around 2am, but it stopped by the time we woke up."
Some residents speculated the noise might be coming from a broken bridge at the docks, but Associated British Ports in Swansea said it was not aware of the issue.
This mystery loud screeching noise was heard in Llanelli recently
A spokesman for Swansea Council said: "We have received a small number of calls about noise disturbance in the Port Tennant area.
"We are continuing to collect information so we can investigate and locate the source of the noise problem."
