The Thursday release of Abdel Baset al-Megrahi, the only man convicted of blowing up Pan Am flight 103 in 1988, was controversial enough. But the reception he received when he returned to Libya has received international condemnation.

Thousands of cheering men were at the Tripoli airport to greet al-Megrahi, some even threw flower petals. White House Press Secretary Robert Gibbs called the scene "outrageous and disgusting".

The 57 year old former Libyan intelligence agent was released from prison on compassionate grounds - al-Megrahi suffers from terminal cancer. The explosion of a bomb for which he was convicted, was hidden in the cargo hold, killing all 259 people on the plane and 11 on the ground in Lockerbie, Scotland.

Gibbs said the White House had been in contact with Libyan authorities. "We've registered our outrage. We have discussed with the Libyans about what we think is appropriate. We'll continue to watch the actions of this individual and the Libyan government."

When asked about al-Megrahi's home coming, President Obama said the warm welcome was "highly objectionable".