A major European human rights body has expressed "deep concern" at the failure to establish a historical investigations unit since the 2014 Stormont House Agreement.
The Council of Europe's Committee of Ministers - Europe's main human rights oversight body - said it was concerned over the failure to reach agreement on legislation on how Northern Ireland deals with the legacy of its past.
It also said it was "imperative" a resolution was reached on investigating the past, particularly given the length of time which had already passed.
The comment comes after the group met on Thursday.
It discussed the implementation of judgements made in 2001 on what are collectively referred to as the McKerr group of cases, taken by the families of a number of individuals killed in incidents involving the security services in the 1980s and 1990s.
These cases involved the killings of Pearse Jordan who was shot after the stolen car he was in rammed police on the Falls Road in 1992; IRA man Gervaise McKerr shot dead by an undercover RUC unit; Patrick Shanaghan, who was suspected by the RUC of IRA membership and who was shot dead by a masked gunman in 1991; as well as the eight members of the IRA killed during an ambush on an attempted terrorist attack at Loughall RUC station on 8 May 1987, as well as innocent bystander Anthony Hughes.
The European Court found that there had been various shortcomings in the investigation of the deaths, including:
As part of its judgement the ECHR made a number of recommendations, focused on establishing a framework for dealing with legacy issues.
In considering the UK's progress of responding to the judgement, the Committee of Ministers "noted with deep concern that the Historical Investigations Unit (HIU) and other legacy institutions agreed upon in December 2014 have still not been established because of a failure to reach agreement on the legislation required".
The Committee also said that it "considered it imperative that a way forward is found to enable effective investigations to be conducted particularly in light of the length of time that has already passed since these judgements became final".
It also noted that the establishment of the Historical Investigations Unit would be further delayed by the planned public consultation process.
The UK government was urged to take all measures to support the Lord Chief Justice's push to deal with legacy issues in Northern Ireland.
The Historical Investigations Unit was proposed as part of the December 2014 Stormont House Agreement. In theory, the body would have full police powers to conduct criminal investigations into killings.
The Council of Europe has oversight for the ECHR, is separate from the European Union, and is made up of 47 member states. Its Committee of Ministers is made up of the foreign affairs ministers from each of its member states.
As a member of the Council of Europe, the UK government is obliged to implement its rulings.