Political progress in the North will depend on the IRA's next steps, US special envoy Dr Mitchell Reiss has said.
In Belfast during meetings with political parties and with Robert McCartney's sisters, Dr Reiss said everything "does hinge on the IRA's response" to appeals for it to endorse democratic norms. "I think it is important that they respond in a very positive and unambiguous way."
However, he said the "hard work of trying to change hearts and minds" goes on every day regardless of the political process. "In some ways they go on their separate tracks," adding that he estimated public opinion to "be ahead of the political process right now".
While claiming that the right response by the IRA was more important than an early response, he expressed fears about a troubled marching season if the IRA let the situation drift.
"Everyone I have spoken with so far recognises the need for the IRA to respond positively and everybody has said sooner is better than later, and I think there is some concern if it does continue to delay much longer that the situation isn't going to remain the same."
Dr Reiss did not say DUP attitudes had hardened following recent political gains. Following his meeting with the party on Tuesday, he said neither did he detect a softening of its position.
"They felt very good about the election result, which is understandable, but I'm not sure there was a hardening or a softening [of their stance]."
Dr Reiss also met the sisters of murder victim Robert McCartney, and heard their assessment that progress was being made in the effort to have his killers brought before the courts.
Speaking after her meeting with him, Paula McCartney said: "We believe the PSNI are a bit more confident than previously. Apparently the witnesses have been giving more information."
Dr Reiss said he was "heartened to hear they were more confident and I very much would like to share their confidence".
Dr Reiss's meetings continue today in Dublin.