A 5G mast was set alight in the Annadale Embankment area of South Belfast on Wednesday night.
Firefighters were called to deal with the incident at around 10.15pm. The fire failed to take hold of the full mast.
They used one CO2 extinguisher to extinguish the fire and the scene was handed over to the PSNI.
The cause of the fire is believed to be deliberate ignition and the incident was dealt with by 11.04pm.
It is the first attack on a 5G mast in the south of city following a spate of attacks in West Belfast over the last two years.
South Belfast MLA Deirdre Hargey condemned the attack.
“This is senseless vandalism on a vital piece of infrastructure that does nothing but cause destruction,” she said.
“Those responsible have caused harm to our community and put lives at risk.”
SDLP councillor Gary McKeown added: "This mindless attack on an essential piece of infrastructure will impact on people's daily lives right across the area. The mobile signal is bad enough in Belfast without ridiculous acts like this adding to it.
"We all rely on our mobile phones as part of our daily lives, but some members of our community are particularly dependent on them, whether it's older people living alone, carers, or people running community organisations or small businesses. This is who will be hit the hardest by this misguided vandalism.
"We've already seen a spate of similar attacks in West Belfast. The last thing anyone wants to see is it spreading to other parts of the city. This has to stop."
Inspector Roisin Brown said: "This is just one of a number of 5G masts that have been set on fire recently and I cannot emphasise enough the dangers of lighting fire to electrical equipment.
“We are treating this as arson, and would ask that anyone with information or dash cam footage to contact us on 101 quoting reference 1956 of 13/08/25.”
Alternatively, you can submit a report online using the non-emergency reporting form here or contact Crimestoppers anonymously on 0800 555 111 or online here.
