Relatives of some of those killed in the Lockerbie bombing have welcomed the naming of two new suspects.
US and Scottish prosecutors have asked Libyan authorities for permission to interview the Libyan men.
The BBC understands they are Mohammed Abouajela Masud and Abdullah al-Senussi.
Abdelbaset al-Megrahi, who died in 2012, is the sole person to have been convicted over the bombing of Pan Am 103 flight in 1988 which left 270 dead.
Stephanie Bernstein, whose husband was among those who was killed in the attack, said she was “surprised, delighted and really gratified” by the news.
“There are many, many people who I hope are not sleeping so well tonight knowing that the Scottish government and the US government are committed to pursuing this case,” she said.
But Jim Swire, whose daughter died, said any prosecution would “need to be supported by very much better evidence” than that used against Megrahi.
Frank Duggan, president of Pan Am 103 Relatives, said he was not confident there would be further prosecutions.
“It’s been 26 years. It’s too long, people are dead, stories have been forgotten,” he said.
“I’d like to think that it will be one small measure of closure but I don’t expect the kind of justice that we all hope for.”
Lockerbie bombing: Key dates
- 21 December 1988: Pan Am Flight 103 from London to New York explodes over Lockerbie, killing 270 people
- 31 January 2001: Abdelbaset al-Megrahi is found guilty of mass murder and jailed for life
- 20 August 2009: Megrahi, who has terminal cancer, is released from prison on compassionate grounds, and returns to Libya
- 20 May 2012: Megrahi dies at home in Tripoli, aged 60
- 15 October 2015: Scottish prosecutors request permission from Libya to interview two new suspects
Both of the newly identified suspects are currently serving prison sentences in Libya, which is in chaos as rival factions fight for control of the country.
Senussi, who is currently awaiting execution in a Libyan jail, was the brother-in-law and intelligence chief of former Libyan dictator Colonel Gaddafi.
Masud is reported to be serving a prison sentence for bomb making.
Both men were named as possible suspects by an American TV documentary last month.
Documentary maker Ken Dornstein’s brother David died in the Lockerbie bombing.
He told the BBC’s Today programme: “We went in with a list of names that had come from the original investigation, pulled out of the tens of thousands of pages of documents. I established many were dead or missing. Ultimately, I concluded there may be three people left.”
On Masud, Mr Dornstein added: “Figuring out simply that he existed would solve many of the unanswered questions to the bombing because he was attached to Megrahi according to the best information there was, including at the airport in Malta on the day that the bomb was said to have been infiltrated into the baggage system and ultimately on to Flight 103.”
Scotland’s Lord Advocate Frank Mulholland QC recently met the US Attorney General, Loretta Lynch, to review progress in the ongoing investigation.
And they have now requested permission from the Libyan authorities for Scottish police and the FBI to interview the new suspects in Tripoli.
The Libyan attorney general declined to comment to the BBC on whether the Libyan government would assist in the investigation.
Megrahi’s part in the bombing has been called into question in a series of books and documentaries.
Pan Am 103 flight was on its way from London to New York on 21 December 1988 when it exploded above Lockerbie in southern Scotland, killing everyone on board and 11 people on the ground.