Dissident republicans are believed to have been responsible for a gun attack on the PSNI in Co Down.
The attack happened as the security forces were conducting a series of searches in the Model Farm Estate in Downpatrick.
Police came under fire during the searches yesterday which they said were part of an investigation into dissident republican activity. The area was sealed off in a follow-up security operation.
No organisation claimed responsibility for the gun attack but it is known that the "Real IRA" has been recruiting in south Down and has also attracted disillusioned former Provisional IRA activists.
The area's SDLP MP, Mr Eddie McGrady, said he was worried by the increase in dissident republican activity in the area. "I am very concerned about the current spate of republican incidents of intimidation, rocket attacks and this shooting incident against police.
"It is clear there seems to be an influx into this area of some sort of paramilitary personnel, presumable members of the dissident IRA group who are intent on creating not just incidents bur murder."
Meanwhile, Sinn Féin Assembly member, Mr Mick Murphy, claimed building sites in Castlewellan, Co Down, had been damaged in petrol bomb attacks which he linked to attempts by dissident republicans to extort money from a local businessman.
Sinn Féin has tabled a motion on anti-sectarianism which the Assembly is expected to debate on Tuesday. Party chief whip, Ms Sue Ramsay, said efforts to have the motion co-signed by all the pro-agreement parties had been "deliberately frustrated" by the Ulster Unionists.
"The reality is that all political parties should stand shoulder-to-shoulder on the issue of sectarianism because it is the real threat to peace in our society."
Sinn Féin has called for another meeting with the Loyalist Commission to discuss moves to end the current street violence in Belfast.
The commission, which is made up of loyalist paramilitaries, politicians, and church and business representative, met Sinn Féin Assembly member, Mr Gerry Kelly, last month.
On Monday, it called for calm in interface areas along the peaceline. It accused republicans of stoking sectarian tensions and said Sinn Féin had a responsibility to end nationalist violence.
The Church of Ireland Primate, Archbishop Robin Eames, welcomed the commission's statement. "I now appeal to the leaders of republican and nationalist areas to seek ways in which they too can encourage a period of calm," he said.