By Reevel Alderson
BBC Scotland Home Affairs Correspondent
The bombing killed 270 people
Further talks have taken place aimed at securing agreement on a compensation deal for relatives of those killed in the 1988 Lockerbie bombing.
The talks in London - the latest in a series - between Britain, the United States and Libya have been aimed at ending UN sanctions imposed on Libya following the atrocity.
The London talks were attended by William Burns, a key member of the US State Department, with responsibility for Middle Eastern Affairs.
He is expected to brief American relatives of those killed in Washington.
If an agreement is reached, relatives from both the UK and the US will study its wording
United Nations sanctions, currently suspended, can only be lifted completely when Libya complies with four key demands.
Among these is adequate compensation and a deal has already been worked out under which a total of $2.7bn would be paid to relatives of those who died, representing $10m per victim.
But another demand - that Libya accepts responsibility for the atrocity - has so far proved to be a stumbling block.
It is understood Britain agreed the wording of a Libyan statement but the Americans were unhappy.
If an agreement is reached, relatives from both the UK and the US will study its wording.
Megrahi was jailed for life for the atrocity
Kathleen Flynn, of New Jersey, whose son John Patrick was among the victims, said US relatives would oppose any lifting of sanctions until Libya complies with other UN demands.
These include revealing all that Tripoli knew of the planning for the bombing in which 259 people on a Pan Am jumbo jet died, along with 11 in the Scottish town of Lockerbie.
The Rev John Mosey, from Herefordshire, whose daughter Helga was a passenger on the jumbo, is sceptical that after 14 years agreement can be reached as the US and UK prepare to go to war against Iraq, another Arab nation.
Abdelbaset ali Mohmed Al Megrahi was jailed for life in January 2001 for the bombing of Pan Am Flight 103, with a recommendation that he should serve at least 20 years.
He was transferred to a Scottish prison from Holland when he lost his appeal against conviction in 2002.
The Foreign Office has confirmed that trilateral talks did take place on Tuesday.
A spokesperson described the meeting as a useful session at which further progress was made.