US President Barack Obama called the release of the Libyan man convicted in the Lockerbie bombing a "mistake," as the State Department warned Tripoli Thursday that a "hero's welcome" would affect future relations, according to dpa. Obama said his administration has been in contact with the Libyan government urging it to place Abdel Basset al-Megrahi under house arrest after he arrives from Britain. "We thought it was a mistake," Obama said in a radio interview Thursday of the release. Scottish authorities released al-Megrahi earlier Thursday on compassionate grounds following a diagnosis that he is suffering from prostate cancer and has about three months to live. He was flown to Libya to spend the remainder of his life with his family.