The Police Service of Northern Ireland (PSNI) has confirmed that a military hand grenade was used in an attack on their officers in west Belfast.
Three police officers were hurt and one of them suffered serious arm injuries when the grenade was thrown by a cyclist who then made off.
The PSNI has described the incident on Friday as "attempted mass murder".
The dissident paramilitary group Oglaigh na hEireann (ONH) said it was responsible for the attack.
The group has been responsible for a number of car bomb attacks on police stations and other targets in Northern Ireland this year.
Chief Superintendent Mark Hamilton described it as "madness".
The attack happened when officers were called to a robbery at a bookmakers on the Shaw's Road.
One officer with serious arm injuries has undergone two operations since the incident. The other two officers have minor injuries.
Chief Superintendent Hamilton said: "We found shrapnel spread all over the place, both sides of the road - shrapnel embedded in the shutters of shops nearby, pieces of the pavement blown out.
"So clearly what Oglaigh na hEireann have said to the community in west Belfast is that they are prepared to kill anybody in their attempts to try and murder police officers going about their lawful business.
He added: "The young officers that go out on duty every day are well aware of the threat that they are personally facing from Oglaigh na hEireann as they go about their work, but the priority is for my officers in west Belfast to go and deal with robberies and burglaries, domestic disputes and RTCs.
"The officers involved here are young people, they are committed to policing this community and that's all they want to do."
The chief superintendent said the officer with the serious arm injury had been operated on for a second time on Sunday evening and that the PSNI was hopeful he would make "a full recovery".
"Clearly when you are attacked with military-type munitions when you are out trying to carry out a role of community policing it is a very deeply shocking and traumatic event for all three officers and to be honest a very shocking event for the community," he added.
"I must say that using these types of weapons in a community where people are moving around and going to a chinese take-away to get their food, using a weapon that has a kill radius that will kill people five or ten metres away is madness."
Mr Hamilton said he could not confirm that the officers had been specifically lured into the attack by the robbery.
"Certainly it doesn't bear the hallmarks of a staged event, the robbery was carried out by a young drunken male who had been in and out of the bookies shop on a couple of occasions who kicked his way behind the counter, stole money and staggered out," he said.
Meanwhile, DUP representative on the NI Policing Board Jimmy Spratt said: "This is a very, very worrying development.
"If you look at the history of the Troubles, in the past grenades were a thing that were not commonly used. I would have serious concerns about the source of this stuff."