Detective Inspector Adrian Brown said: “Our investigation into this incident is progressing and today we arrested three men in Belfast aged 21, 34 and 60, as well as a 29 year old man in Dungannon.
“They were all arrested under the Terrorism Act and have been taken to Musgrave Serious Crime Suite where they are currently being questioned.
“The device, which was explosively formed projectile – EFP – a weapon that is primarily designed to attack armoured vehicles and kill the occupants within, caused widespread disruption on October 30.
“While it was clearly designed to kill or seriously injure police officers serving the local community in west Belfast, it was left in a position where there was every possibility that it could have killed or maimed members of the public.
“Those responsible showed callous disregard for the safety of members of the public and police officers and we were extremely fortunate that no one was killed or seriously injured.
“If anyone has any information about this incident please contact detectives on 101.
“Or alternatively information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”