Republicans have been blamed for carrying out two paramilitary-style shootings, days after Sinn Féin vowed it would not cooperate with the new body which will monitor ceasefires.
In a brutal attack in the nationalist Short Strand area of east Belfast, a man was shot in both elbows and ankles.
The victim, believed to be in his forties, was shot in Beechfield Street at around 11pm on Monday. It is understood the Provisional IRA was responsible for the shooting.
Earlier a teenager was shot in both ankles in the predominantly republican Poleglass estate on the outskirts of west Belfast.
The 18-year-old man was found lying at Glenwood Green at 8.15pm on Monday. Sinn Féin Short Strand councillor Joe O'Donnell said his party's position on so-called punishment shootings and beatings was "very clear and well documented".
"We don't believe that kneecappings or anything of that nature solves anything in communities," he said.
"But these sorts of things can happen in the vacuum that exists because of the lack of effective policing."
Referring to the shooting in his own area, Mr O'Donnell said: "I don't have any idea who was responsible for it.
"There are all sorts of difficulties in this area."
Ulster Unionist former assembly member Michael McGimpsey blamed republicans for the shootings and said they demonstrated "why the Inter-national Monitoring Commission (IMC) is needed".
The British and Irish governments last week said the IMC, which is to monitor paramilitary activity in Northern Ireland, was a vital move towards restoring devolved government.
The four-member commission will have the discretion to recommend that the assembly or the Secretary of State should sanction political parties linked to paramilitary activity.
Legislation relating to the IMC started its passage through Westminster yesterday (Tuesday). Sinn Féin president Gerry Adams last week made it clear that his party would not cooperate with the IMC.
"Why should we cooperate with something we are against," he said.
Mr Adams said the commission was established to appease unionism and that it had been "tinkered with and diluted" to meet the needs of factions within unionism.
"While we fully support people being held to account we will not support a mechanism that is totally outside the agreement," he said.
Mr McGimpsey last night said: "The IMC is there to look at paramilitary activity such as punishment shootings and will require the Secretary of State to take action if the assembly itself cannot get a vote.
"This mechanism has always been in the Good Friday Agreement."
The legislation "clearly must allow the IMC to declare when a ceasefire is broken", he added.
"There must be ramifications for those who breach ceasefire and Sinn Féin will be politically accountable for the (Provisional) IRA's actions.
"The IRA's war is over, it is counter-productive and embarrassing for Sinn Féin.
"The IRA has to go away in the same way that all paramilitary groups have to go away."
Since January, republican groups have carried out 48 paramilitary-style shootings and 28 beatings.
Loyalist groups have carried out 59 paramilitary-style shootings and 59 beatings this year.
