Two viable pipe bombs were found in north and west Belfast. on Monday.
Homes were evacuated in the Brae Hill Link area of north Belfast following the discovery of a suspicious object in the area, and a suspicious object was also discovered at Old Brewery Lane in west Belfast.
Army Technical Officers were tasked to both scenes and on Monday afternoon police said both devices were viable pipe bombs which have been taken away for forensic examination.
Police are investigating a link between the two incidents and have appealed for anyone with information to come forward.
Earlier on Monday morning a security alert closed the M1 motorway for around five hours.
SDLP Councillor Tim Attwood hit out at those behind the three alerts.
“These series of security alerts across Belfast are deeply disruptive for families on the school run and for people going to work,” said Mr Attwood.
“The elaborate and cynical hoax at Kennedy way this morning led to major chaos on the roads and resulted in many people being late for work and missing appointments.
“People in this city deserve to go about their everyday lives without the fear of security alerts and road closures.
“I want to commend the PSNI for their work to make these areas safe and allow people to return to normality as soon as possible.”