Dozens of people protested Colonel Gaddafi's visit to the UN
Protesters have greeted Colonel Muammar Gaddafi on his arrival at the United Nations in New York.
Relatives of Lockerbie bombing victims were among those demonstrating against the Libyan leader, who was to address the general assembly.
Supporters of the formerly outcast North African leader also gathered outside the UN to welcome him.
The release of the Libyan man convicted of the 1988 attack over southern Scotland caused controversy in America.
Abdelbaset Ali al-Megrahi, who is terminally ill, was freed on compassionate grounds by the Scottish government in August.
Colonel Gaddafi has not spoken to the General Assembly in 40 years
On Wednesday, Prime Minister Gordon Brown repeated his criticism of the jubilant welcome Megrahi received on his return to Libya and indicated he would not be attending Colonel Gaddafi's first speech to the UN in 40 years.
"I don't think I will be there for that. I have made my views very clear to the Libyans," he told BBC Radio 5 live.
"The way that Megrahi was received in Libya was completely unacceptable. I think it did a lot of damage to the Libyans' reputation in the international community."
The controversy has heightened the sensitivity of the appearance of Col Gaddafi in New York.
Original plans for him to stay at a five-acre plot in New Jersey were changed amid local opposition - many of the victims' relatives live in the state.
Instead the delegation has opted for a site in suburban New York.
Jack and Kathleen Flynn were disappointed by Megrahi's release
Among the protesters outside the UN building were Jack and Kathleen Flynn who lost their 21-year-old son JP in the 1988 attack on Pan Am flight 103, in which 270 people died.
Mr Flynn said: "We are trying to say Mr Gaddafi is a murderer and he should not be honoured at the UN in any way.
"Yet he is being honoured at the UN, allowed to speak and that is absolutely horrible because he ordered the bombing of Pan AM 103."
Mr Flynn, who travelled from New Jersey to mount his protest, added: "I went to the trial every day, I saw all the evidence - it was obvious that he ordered Megrahi to put the bomb on Pan Am 103."
Mrs Flynn said she believed the compassionate release of Megrahi, who is suffering from terminal cancer, had damaged relations between Scotland and the United States.
She said: "I think the Scots have let us down tremendously, we have lost faith in the Scots.
Megrahi is the only man convicted of the Lockerbie bombing
Mrs Flynn said she was "absolutely shocked" that Scottish Justice Secretary Kenny MacAskill "took it upon himself to release Megrahi".
She dismissed the diplomatic moves made to heal the rift after the US government said it wanted to move on.
She said: "My government might want to move on, but we are not going to let them forget and we are not forgiving the Scots for what they did."
Colonel Gaddafi was due to speak after US President Barack Obama's inaugural address to the UN.