A service has taken place in southern Scotland to remember the victims of the Lockerbie bombing 30 years on.
Wreaths were laid at a memorial garden in the town to honour the 270 people killed when Pan Am Flight 103 was blown up on 21 December 1988.
Jeff Brown, moderator of the presbytery of Annandale and Eskdale, paid tribute to those lost in a "senseless act".
Eleven people in Lockerbie died along with 259 passengers and crew on board the plane bound for New York.
It was the biggest mass murder on British soil in recent history.
The majority of those on board the plane which fell on the town in south-west Scotland were American.
A new permanent memorial to the victims has also been unveiled at the FBI headquarters in Washington DC.
Services were later held at Syracuse University in New York State and Arlington National Cemetery in Virginia.
The Lockerbie wreath-laying saw victims' relatives join members of the community who assisted in the aftermath of the atrocity.
Mr Brown, who conducted the ceremony at Dryfesdale Cemetery, said: "We remember loved ones taken in a senseless act of violence, we remember lives, families and communities torn and broken.
"We stand together in the silence and peace of this place in our act of remembrance to keep faith with them."
He also offered thanks for the "simple acts of kindness" which had helped to "ease the pain of loss caused by this callous act".
The Lord Lieutenant for Dumfriesshire Fiona Armstrong read out a message from the Queen and paid tribute to the "remarkable community" in the town.
"Please convey my warm thanks to the people of Dumfriesshire for their kind message, sent on the occasion of their Remembrance service to commemorate the 30th anniversary of the Lockerbie bombing, which is being held today," the Queen said.
"I send my prayers and good wishes to all those who will be marking this solemn anniversary."
Scottish Secretary David Mundell, who is from the town, also attended the service and laid a wreath.
"Lockerbie lost its anonymity that night," the MP for Dumfriesshire, Clydesdale and Tweeddale said.
"We went from a quiet small town to a centre of global attention in a few seconds.
"That was the scale of the challenge local people have faced, aside from the horrors of the air disaster itself."
He said the people of Lockerbie had retained their "dignity and stoicism" throughout and said "strengthening and deepening" the relationships forged with the US should be a priority.
First Minister Nicola Sturgeon said the victims of the bombing would always be remembered.
"Thinking today of Lockerbie and all those whose lives were lost or deeply affected by what happened on this day 30 years ago, " she said.
"We will never forget."
Prime Minister Theresa May also tweeted: "Today we remember those who died in the Lockerbie bombing 30 years ago.
"On this tragic anniversary, my thoughts are with the families of those who lost their lives and the Lockerbie community."
In the US, a plaque unveiled at a ceremony at the FBI headquarters in Washington revealed the bombing "transformed how the FBI investigates terrorism, works with international partners and cares for victims".
Scotland's top law officer Alison Di Rollo was among 400 guests at the service, where she pledged to work in close co-operation with the US authorities if new evidence on the attack became available.
It is still under investigation by a team of Scottish prosecutors.
Ms Di Rollo, Scotland's solicitor general, said: "As a prosecutor I cannot guarantee that the current investigation will uncover enough evidence to support criminal proceedings but I can - and do - promise that the Lord Advocate and I, along with the prosecution team and the Police Service of Scotland, will remain committed to this investigation and to working as closely as we ever have with our US colleagues."
Syracuse University remembered its victims at a memorial service and there was also a service at Arlington National Cemetery in Virginia, where a cairn made from Lockerbie stone stands in memory of those who died.
Back in Scotland, a Walk of Peace has been arranged by the Church of Scotland on Saturday to remember those who died.
People will climb Burnswark Hill near Lockerbie in silence following a special service at Tundergarth Parish Church the previous day.
The only person ever to be convicted of the bombing, Abdelbaset al-Megrahi, died in 2012 after being released from Greenock jail on compassionate grounds.
His family is currently making a third attempt to appeal against his conviction.
The Scottish Criminal Cases Review Commission is considering whether there are grounds to refer his case to the appeal court.