The Obama administration expressed deep disappointment Thursday over the release of the Lockerbie bomber, saying the decision to let the Libyan terrorist go home was made by the Scottish government in spite of "extensive" appeals from U.S. officials.

Scotland's Justice Secretary Kenny MacAskill announced Thursday morning that Abdel Baset al-Megrahi, who has terminal prostate cancer, would be released to Libya. He has since boarded a plane to fly home.

Megrahi was the only person convicted in the December 1988 bombing of a Pan Am flight over Lockerbie, Scotland, that killed 270 people. He had been sentenced to life in prison, but was released on compassionate grounds.

As family members of the victims decried the decision, U.S. officials scolded the Scottish government for ignoring their pleas.

"The interests of justice have not been served by this decision," Attorney General Eric Holder said in a statement, saying he was "extremely disappointed" by the release. "There is simply no justification for releasing this convicted terrorist whose actions took the lives of 270 individuals, including 189 Americans."

He said Megrahi showed no compassion for innocent life and that he should have had to serve out his sentence.

White House Press Secretary Robert Gibbs said the United States "deeply regrets" the move.

"As we have expressed repeatedly to officials of the government of the United Kingdom and to Scottish authorities, we continue to believe that Megrahi should serve out his sentence in Scotland," he said in a statement. "On this day, we extend our deepest sympathies to the families who live every day with the loss of their loved ones. We recognize the effects of such a loss weigh upon a family forever."

The White House said that it, Secretary of State Hillary Clinton, Holder and other U.S. officials had "extensive contacts" with their counterparts in Britain to oppose the release.

Clinton also released a statement saying the United States is "deeply disappointed" by the decision. She stressed that the midair bombing of the London-to-New York plane killed 189 Americans and that Megrahi deserved to stay in prison.

"We have continued to communicate our long-standing position to U.K. government officials and Scottish authorities that Megrahi should serve out the entirety of his sentence in Scotland," Clinton said. "Today, we remember those whose lives were lost on December 21, 1988 and we extend our deepest sympathies to the families who live each day with the loss of their loved ones due to this heinous crime."