The Scottish government has again defended its decision to release the man convicted of the Lockerbie bombing, Abdelbaset Ali Mohmet al-Megrahi.

Edinburgh was responding to remarks in a letter from the head of the United States FBI that he was “outraged” at the decision. US President Barack Obama earlier described the release as “a mistake”.

A Scottish government spokesman said the Libyan was released only after due process and consultation with the parole board and prison governor. He added that "Compassionate release is not part of the US justice system but it is part of Scotland's."

Al-Megrahi was sentenced to life imprisonment for the attack on a PanAm aircraft above the Scottish town of Lockerbie, in which 270 people died, most of them US citizens. He was released on Thursday because he is suffering from terminal prostate cancer.