Former US diplomat Dr Richard Haass, who is overseeing political negotiations in Northern Ireland, has said he hopes to make measurable progress on three key problem areas between now and the end of the year.

The former US envoy to Northern Ireland made his remarks at a news conference in Belfast.

Dr Haass was asked by Northern Ireland's First and Deputy First Ministers Peter Robinson and Martin McGuinness to seek solutions to flags and emblems, parading and how to address the past.

He said he hopes to make progress on the issues because each has an impact on the wider environment and context.

Dr Haass, who will be working with Harvard academic Professor Meghan O Sullivan, described the timetable as ambitious but possible.

In negotiation, he said, the single most important thing is often the willingness of the respective sides to make compromises and to be sufficiently strong to make the case for those compromises with their respective constituencies.

No outsider can substitute for the willingness of the insiders to sign up and to sell it to the constituencies they represent, he added.

Dr Haass has the support of the British, Irish and US governments, but he is an independent chairman of the process now under way.