British Prime Minister David Cameron said the decision to release the Lockerbie bomber was utterly wrong on Monday, on the eve of his first visit to Washington as premier.
Abdelbaset Ali Mohmet al-Megrahi was released by the Scottish government on compassionate grounds 11 months ago after the cancer sufferer was given three months to live, but he is still alive.
Megrahi was the only person convicted of the 1988 bombing of a US jet over the Scottish town of Lockerbie. Some 270 people were killed.
His release sparked outrage in the US, where most of the victims were from.
"The US-UK relationship is a strong relationship," Cameron told BBC television.
"There'll be a lot of things that we'll be talking about: Afghanistan, BP, I'm sure Al-Megrahi will be raised as well."
Anger over his release has been ratcheted up by claims about BP, which is already under fire over the Gulf of Mexico oil spill.
London has insisted there was no evidence linking Megrahi's release to protecting a lucrative BP oil deal with Libya, amid mounting US concern.
"I have no idea of what BP did. I'm not responsible for BP," said Cameron, who became prime minister in May.
"All I know is, as leader of the opposition, I couldn't have been more clear. I thought the release of al-Megrahi was completely and utterly wrong.
"He was convicted for being the biggest mass murderer in British history. I saw no case whatsoever for releasing him from prison. I've said that a year ago when we were told that he had three months to live."
Cameron meets US President Barack Obama at the White House on Tuesday.
On Wednesday, he will be briefed on Afghanistan operations at the Pentagon before travelling to New York to meet business leaders, talks at the UN and a dinner hosted by the city's mayor Michael Bloomberg.
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