LONDON - Ceremonies were held Sunday in the Scottish town of Lockerbie to mark the 20th anniversary of the bombing of Pan Am Flight 103, in which 270 people were killed.

More than 150 people attended a wreath-laying ceremony Sunday at Lockerbie's Dryfesdale Cemetery, which has a memorial stone for those who died.

Two churches in the area held services to coincide with the moment the plane came down, just after 1900GMT on Dec. 21 1988. Services are also being held at Heathrow Airport in London and in the United States.

All 259 people on board the flight from Heathrow to New York were killed when a bomb exploded on the plane as it flew over Lockerbie. Another 11 people died on the ground.

Libyan secret agent Abdel Basset Ali al-Megrahi is the sole person to have been convicted of the bombing, but he has won the right to appeal against his January 2001 conviction by successfully convincing judges that a "miscarriage of justice" may have occurred during his trial.

Al-Megrahi, who is suffering from incurable prostate cancer, is due to have his appeal heard next year.

The Lockerbie bombing drove relations between Libya and the West to the breaking point. But the dynamics of the case have changed as Libyan leader Col. Moammar Gadhafi engineered a rapprochement with the West in the dangerous times following the 9/11 attacks on Washington and New York.

The self-styled revolutionary leader, who once seemed to thrive on confrontation, has renounced terrorism and voluntarily dismantled his clandestine program to develop nuclear weapons.

Britain, the United States and Libya are now publicly committed to working together to contain the threat of international terrorism.

Libya has paid several billion dollars to the families of Lockerbie victims, and has accepted "general responsibility" for the attack.

U.S. officials, and the families involved, said in November that Libya had made the final compensation payments. These acts of contrition have allowed Libya to restore diplomatic ties with Britain and the United States and to have United Nations-imposed sanctions lifted.