Updated: 8.10am 

A 19-year-old man was arrested overnight on suspicions of having placed a homemade bomb outside the Labour Party's headquarters on Thursday. 

The explosive device was found inside a waste bin outside of the building. 

It is understood that police zeroed in on the teen at a garage in Ħamrun, where he had been living. 

Police later clarified that the suspect had been picked up from a site in Triq Guze Pace in Sta Venera. 

Explosive material was found in that garage and the residents of the apartment block on top of it were evacuated from their homes as a precaution. 

The material found in the garage is known as TATP,  a volatile explosive that is also called 'mother of Satan'. It is often used in terrorist attacks as it is potent and can be made out of household supplies.

The AFM Explosives Ordnance Disposal unit and the police at the scene on Friday morning. Photo: Jonathan Borg

Residents who spent the night out of their homes are expected to be able to return there later this morning.

The suspect was identified through CCTV footage, with sources saying that police had received reports of the man "acting oddly" in various other places on Thursday.

He was wearing the same clothes as the person spotted on CCTV outside Labour HQ. 

An explosives team was called to Mile End on Thursday after the building's security officials spotted what was described as a "small device" outside the Labour Party's headquarters. 

Neighbours also reported hearing a "small explosion" coming from a dust bin very early on Thursday morning. 

No one was injured in the incident but the building was evacuated while a police investigation was conducted. 

The building was given the all-clear for people to return by 1pm.