Relatives of the victims of the Lockerbie bombing have reacted angrily to the news that Libya has won a seat on the UN Security Council just more than a year after the US removed the north African nation from the list of state sponsors of terrorism.

Relatives in the US said their government should have done more to prevent Libya from getting a seat on the UN's most powerful body as they still believe the country to be responsible for the 1988 bombing of PanAm103 in which 270 people were killed.

However, Dr Jim Swire, who lost his daughter Flora in the bombing, said he welcomed the move.

Abdelbaset Ali Mohmed al Megrahi, the Libyan convicted of the bombing, is serving his 27-year sentence in HMP Greenock. He was granted fresh leave to appeal in June after a three-year investigation by the Scottish Criminal Cases Review Commission which found six grounds on which the conviction may have been a miscarriage of justice.

Libya was demonised for years by the US as a sponsor of various terrorist groups. It was also blamed for a West Berlin disco bombing that killed two American soldiers in 1986.

Relations between Washington and Tripoli have improved since Libya's decision in the wake of the US-led invasion of Iraq in 2003 to dismantle its clandestine nuclear weapons programme. Asked about Libya joining the council, US deputy ambassador Alejandro Wolff said "the United States doesn't reveal how it votes on these elections".

But he said "the world changes", citing the responsible role that Second World War enemies Germany and Japan now play. "We look forward to working with all new members that are elected."

Libya's UN Ambassador, Giadalla Ettalhi, stressed the 178 "yes" votes Libya received in the 192-member General Assembly.

He said: "It means I can say we are back in the international community. I think our relations with the US nowadays are back to normal and I think they have not worked against our candidacy."

Glenn Johnson, who lost his 21-year-old daughter Beth Ann in the Lockerbie bombing and chairs the group Victims of PanAm 103, which represents families of about 160 of the 270 victims, said Libya still owes the families $2m each as part of a deal that Libya made with the US. The families have already received $8m.

"We really felt let down when the State Department didn't make the objections it has in the past," Mr Johnson said. "The US allowed (Libya) off the hook even though for some reason Libya decided it didn't have to take the last step of the agreement."

Mr Wolff, the US envoy, said: "The compensation issue is something we are pursuing bilaterally with the Libyan government."