Representatives of the five main political parties in Belfast are facing mounting pressure to reach some sort of settlement on dealing with contentious parades and the legacy of Northern Ireland's troubled past. With the former US envoy Richard Haass due to return to the US tomorrow, all sides have until later today to come to an agreement. As he headed to the negotiating table at an hotel in east Belfast this morning, Sinn Fein's Gerry Kelly, a member of the Stormont Assembly, said: "There are issues that can be sorted if the political will is there." The White House and Northern Ireland Secretary Theresa Villiers have already urged the parties to come to an agreement. The issue surrounding the flying of flags is deadlocked but there is optimism there will be progress on parades and the past. Dr Haass - president of the Council on Foreign Relations in New York and an envoy to Northern Ireland from 2001 to 2003 - and his vice chairman Professor Meghan O'Sullivan returned to Belfast after the talks broke up just before Christmas. Today, the parties discussed a sixth draft set of proposals put forward by Dr Haass and Dr O'Sullivan, a Harvard professor with experience in post-conflict Iraq. They were asked last July by First Minister Peter Robinson and deputy First Minister Martin McGuinness to submit recommendations for dealing with the region's unresolved issues. It will be hugely embarrassing for the Stormont executive if the parties fail to meet today's deadline for a settlement. Dr Haass has warned them it is time to "fish or cut bait". On Saturday, Mr Robinson said parts of the proposed agreement were "unworkable". Sinn Fein president Gerry Adams, whose party represents most nationalists, has said a deal can be done and appealed to talks participants to overcome their differences. All parties agree that the views of victims should be integral to any process for dealing with the past, but it has been difficult to decide what that mechanism should be, whether limited immunity from prosecution should be offered to those who give information about shootings, bombings and other atrocities, and what powers any new commission for investigating the past should have. A replacement for the Government-appointed Parades Commission, which was heavily criticised by unionists after it rerouted a loyal order parade away from the nationalist Ardoyne part of North Belfast last summer following years of annual violence on July 12, was one of the keys issues discussed today. Ms Villiers said: "From my many conversations on this over recent days, I am encouraged about the prospects for agreement, although some key issues are yet to be resolved, particularly on the past."