Tony Blair has been asked to appear before a US hearing on the Lockerbie controversy, according to reports.
The former prime minister could appear alongside ex-foreign secretary Jack Straw who has been invited to the US Senate Foreign Relations Committee meeting to discuss the release of Lockerbie bomber Abdelbaset al-Megrahi.
US senators want to investigate suspicions that oil giant BP may have had a hand in the affair.
The Scottish Government said it had formally declined the request for Scottish Justice Secretary Kenny MacAskill and Scottish Prison Service health boss Dr Andrew Fraser to attend.
Former UK Justice Secretary Jack Straw said he had yet to receive formal notification of the request to attend the US Senate Foreign Relations Committee meeting on July 29.
The ex-foreign secretary said he would have to consult with the Foreign Office and former Prime Minister Gordon Brown before complying with the request to discuss in person the circumstances surrounding the release of the Lockerbie bomber last year.
Mr Straw said: "Before coming to any decision as to whether to accept this invitation, I shall be consulting Gordon Brown, as Prime Minister at the time, and seeking the advice of the Foreign Office.
"It is, in my experience, highly unusual for the legislature of one sovereign state to conduct an inquiry into decisions of another sovereign state, including, as in this case, decisions by a devolved administration on the release of a prisoner."
A BP spokesman confirmed chief executive Tony Hayward had been asked to attend. He said: "We have received the invitation and we are considering it."
Cancer-stricken Megrahi was released from Greenock jail on August 20 last year, having been given three months to live. He is still alive and living with his family in the Libyan capital, Tripoli.