The man who controversially freed the Lockerbie bomber has insisted he is accountable to the Scottish Parliament and "no other".
US senators had wanted to question Scottish Justice Secretary Kenny MacAskill on his decision to grant compassionate release to Abdelbaset Ali Mohmed Al Megrahi.
But Mr MacAskill turned down the request to appear before the Senate's Foreign Relations Committee.
On Friday, he told delegates at the SNP annual conference in Perth that he answered to Holyrood and no-one else, "irrespective of their size, status or power".
The Libyan remains the only person convicted of the 1988 bombing of Pan Am Flight 103 over Scotland, in which 270 people died - most of them Americans.
Mr MacAskill did not explicitly mention the Lockerbie case or Megrahi in his address to the SNP conference. But he told delegates it was a "great privilege" to be both a member of the Scottish Parliament and the country's Justice Secretary.
To loud applause, Mr MacAskill stated: "It is those electors that I am accountable and to that institution that I am answerable. To no other, irrespective of their size, status or power."
Mr MacAskill released the Libyan, who has prostate cancer, on compassionate grounds almost 14 months ago after the bomber was given three months to live. But Megrahi remains alive.
The decision sparked fury in America and was condemned by President Barack Obama's administration.
Mr MacAskill said he believed he had "upheld the laws and followed the values of Scotland".