Barack Obama condemns Lockerbie Bomber's release

Mr Obama said the decision by the Scottish Government was a "mistake" and called on Libya to immediately place Megrahi under house arrest in his home country.

His comments reflected the anger held by many American families who lost loved ones in the 1988 bombing of Pan Am Flight 103. Of the 270 victims of the terrorist attack, 189 were from the US.

The release of the man convicted over the atrocity yesterday was met by disbelief by some in America.

Many could not understand how the Scottish justice system could show compassion for Megrahi, freeing him to live out the remaining weeks of his life in his homeland.

Susan Cohen, of New Jersey, who lost her 20-year-old daughter, Theodora, in the bombing, said: "I think it's appalling, disgusting and so sickening I can hardly find words to describe it."

Likewise Kara Weipz, also of New Jersey found it difficult to contain her anger. Her 20-year-old brother Richard Monetti was among the American victims.

"I don't understand how the Scots can show compassion. It is an utter insult and utterly disgusting," Ms Weipz said.

Cable news channels showed footage of Megrahi's homecoming in Libya, complete with cheering crowds, in a move that further angered those who lost loved ones.

Criticism of the Scottish decision came from the highest level.

In a live radio interview, the president said the United States administration had been in contact with the Scottish Government to register its objections.

Mr Obama said he had contacted families of the victims and indicated to them that he believed the release was inappropriate.

He added: "We have been in contact with the Scottish Government indicating that we objected to this. We thought it was a mistake.

"We are now in contact with the Libyan government and want to make sure that if this transfer has taken place, that he is not welcomed back in some way but should instead be under house arrest."

It followed earlier condemnation from the White House press secretary and US attorney general Eric Holder.

In his attack on the decision, Mr Holder said it had "no justification".

He said: "We are extremely disappointed with the Scottish Executive's decision to release Abdelbaset Ali Mohmed Al Megrahi.

"The interests of justice have not been served by this decision."

Mr Holder added: "Megrahi did not show and has not shown compassion for innocent human life, and as we communicated to the Scottish authorities and the UK Government, it continues to be our position that he should have been required to serve the entire sentence handed down for his crimes."

Speaking on CNN, Scottish Justice Secretary Kenny MacAskill attempted to defend his decision to an American audience.

He said: "In Scotland, justice is tempered with compassion. That is why he has been allowed to go home to die.

Mr MacAskill added: "I'm showing his family some compassion. I accept it is a compassion not shown to families in the United States or in Scotland.

"But we have values and we will not debase them and we will seek to live up to those values of humanity that we pride ourselves on."

Cameron: Lockerbie decision is 'wrong'