Libya's prime minister has told the BBC his country does not accept guilt for the Lockerbie bombing or the shooting of Wpc Yvonne Fletcher.
The 1988 bombing over Lockerbie killed 270 people
Shukri Ghanem told Radio 4's Today the Wpc Fletcher issue was "settled".
Relatives reacted with dismay, saying the comments were "out of line" with Libyan admissions of responsibility.
But UK Foreign Secretary Jack Straw said: "As far as the British Government is concerned, the position of the Libyan Government remains unchanged."
Mr Straw said he would examine the "reported comments", but the Libyan Government had made its stance on both Lockerbie and Wpc Fletcher's death "crystal clear" in formal letters.
Dr Ghanem's comments have sparked questions about Tony Blair's proposed visit to Libya.
His official spokesman said the "context" of any visit would be that Libya accepted Britain's positions on Lockerbie, Wpc Fletcher and weapons of mass destruction.
He said: "We will want to clarify what the prime minister of Libya said with the Libyan authorities.
"There does seem to be some disparity because if you look at the letter the Libyan government sent to the president of the United Nations Security Council about Lockerbie, paragraph three says Libya accepts responsibility for the actions of its officials."
Earlier, asked if paying compensation over Lockerbie did not mean acceptance of guilt, Dr Ghanem agreed that it did not - and said the effect of sanctions had prompted a deal.
"We feel that we bought peace. After the sanctions and after the problems we faced because of the sanctions, the loss of money, we thought it was easier for us to buy peace and this is why we agreed on compensation."
But the relatives insisted they had not been bought off, and expected Libya to take responsibility and co-operate with further investigations.
It was reported on Tuesday that the US is likely to scrap a ban on travel to Libya as part of an easing of sanctions in reward for Tripoli giving up weapons of mass destructions.
Dr Ghanem's comments come after recent conciliatory moves from Libya's foreign minister.
In a landmark meeting earlier this month Mohammed Abdulrahman Shalgam agreed with Mr Straw to increase co-operation in finding Wpc Fletcher's killers.
The police officer was shot in 1984 outside the Libyan Embassy in London; the incident led the UK to break off diplomatic links.
Dr Ghanem told Today he agreed with the Libyan lawyer who investigated the case who said there was no real evidence the bullet came from the embassy, and no proof a Libyan was to blame.
He said he considered the Fletcher case to be closed.
It has been said the authorities failed to fully investigate the shooting.
But Dr Ghanem said: "The whole subject has been settled to the satisfaction of both governments."
The Metropolitan Police Federation has said it is inconceivable Libya did not know who had fired the shots.
In 1999 Libya accepted "general responsibility" for the killing and agreed to pay compensation to her family.
Wpc Fletcher's mother, Queenie Fletcher, 70, said from her home in Wiltshire on Tuesday that she did not want to comment on the row.
Former British ambassador to Tripoli Oliver Miles said Mr Ghanem was returning to a line Libya had previously taken, and continued to accept responsibility
for the actions of their officials without necessarily admitting having control over them.
"They don't accept they have the guilt of the murders."
However, he said the recent rapprochement should continue.
Dr Jim Swire, who lost his daughter in the Lockerbie bombing, was surprised, saying:
"It's out of line with everything Libya has been saying, it is one
person saying this, the prime minister, and nobody knows why he has said this."
Pamela Dix, who lost her sister, told BBC News 24 that Britain must do more to press Libya to help with ongoing investigations.