The judges presiding over the Bloody Sunday inquiry are to have direct discussions with high-ranking British defence officials and RUC officers on security issues concerning military witnesses.
The tribunal chairman, Lord Saville, announced yesterday that it wants more information on the security situation before it makes a crucial ruling on where soldiers should give their oral evidence.
Last week the inquiry heard extensive submissions from Britain's Ministry of Defence and all the interested parties on the hotly contested issue of the venue for testimony by soldiers who were in Derry on January 30th, 1972, when 13 civilians were shot dead in the Bogside.
More than 200 British soldiers are due to be called to give direct evidence on the killings, although only some 20 members of the Parachute Regiment have admitted firing live rounds.
Although the soldiers have been granted anonymity (other than senior officers whose names are already well known), their lawyers argue that they should not have to come to Derry, because of security considerations.
The Ministry of Defence said the risk to military witnesses in Derry, particularly the threat from dissident republican terrorists, was of major concern.
The families of the Bloody Sunday victims strongly oppose any transfer of the inquiry outside Northern Ireland. The tribunal has raised the possible compromise that the soldiers' evidence could be heard over a live video link from a secret location in Britain.
In evidence yesterday, an officer of the Derry Civil Rights Association, the local organisers of the protest march against internment on January 30th, 1972, claimed there were tensions between that group and Mr John Hume, who was then deputy leader of the SDLP.
Mr Michael Havord, an Englishman who served for 12 years in the British Navy, said he moved to Derry after leaving the navy and joined Derry CRA in 1971 because of internment.
He said that there was a unique situation in Derry: "Basically we had two civil rights movements." There was Mr Hume and his supporters, and there was the Derry CRA.
Mr Havord said Mr Hume told him he considered the Derry CRA politically dangerous. Mr Havord did not know whether this was because Mr Hume considered the CRA chairwoman, Ms Brigid Bond, to be a danger to his personal position if she stood for election, or because he might have considered the CRA as too far to the left.
Mr Havord said there was strong pressure on the Derry CRA to allow John Hume to speak on the platform on Bloody Sunday. However, the policy of Derry CRA was that anybody who was to speak - with the exception of Lord Fenner Brockway - should have taken part in the march, and Mr Hume had announced that he was not going to march.
Another witness, Ms Mavis Hyde, who was secretary of Derry CRA, agreed in evidence that a Mr Reg Tester was a committee member of the association.
Mr Bilal Rawat, for the tribunal, put it to her that Mr Tester had made a statement to the inquiry in which he says: "At the time of Bloody Sunday I was a command staff quartermaster for the Official Irish Republican Army." The witness said she was not aware at that time of what Mr Tester's affiliations were.
The inquiry continues today.