Unionists have accused republicans of failing to support police and emergency services assisting those injured in a helicopter crash in south Armagh.
A British army Lynx helicopter crash-landed in Crossmaglen on Sunday evening in bad weather, injuring six officers, two of them seriously.
North Antrim DUP Assembly member Ian Paisley jnr said: "What really concerns me is the complete lack of political leadership on the ground in Crossmaglen from republican leaders telling young people that this sort of behaviour is totally unacceptable and it must stop."
In a reference to his party's demand for deliverance by Sinn Féin of active support for policing, he added: "We need to see that leadership and we need to see it fast."
Sinn Féin said its representatives worked to disperse a crowd which had gathered at the crash site and that it took no pleasure from the injuries to those on board the helicopter.
After the crash-landing the PSNI issued a statement claiming that rescue workers were attacked by those throwing missiles, fireworks, stones and snowballs. Later the ambulance service said one of its vehicles was stopped by a crowd as it ferried the injured to hospital.
Director of operations, Brian McNeill, said: "We are only trying to do our job and it is difficult enough going to a major incident like that without having to deal with unruly crowds, and it is unacceptable."
But Sinn Féin MP Conor Murphy said his party was alone in trying to stop children throwing missiles at the site. "There was a blizzard blowing and it was dark, so I couldn't say what was being thrown. I saw kids throwing snowballs. We asked them to disperse and the vast majority of them did and that was the end of it."
Asked if he condemned those who hampered those attempting to assist those hurt in the crash, Mr Murphy added: "Yes. Not only did we stop them doing that, we took action on the ground. Other people were commenting on this. I did not see another single elected representative apart from Sinn Féin personnel on the ground here."