The United States has demanded that Libya retract a statement by its prime minister denying Libyan responsibility for the 1988 Lockerbie bombing.
Compensation does not indicate guilt, said Mr Ghanem
The State Department has delayed plans to lift restrictions banning Americans from travelling to Libya, reportedly in protest at Shukri Ghanem's comments.
Dr Ghanem told BBC radio that Libya had "bought peace" by paying compensation to the bombing victims.
Relations between the US and Libya have recently warmed after years of enmity.
The US was due to lift the travel restrictions on Tuesday, but State Department officials were quoted as saying the step had been postponed in the light of Dr Ghanem's remarks.
Last August, Libya agreed to pay $2.7bn to the families of the 270 people killed when Pan Am Flight 203 was blown up over the Scottish town of Lockerbie.
It also wrote a letter to the United Nations Security Council accepting responsibility for the bombing, opening the way for the lifting of sanctions and renewed ties with the West.
But in surprise remarks, Dr Ghanem said: "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."
US officials demanded that Dr Ghanem withdraw his comments.
"We expect the Libyan to retract this statement," said State Department spokesman Richard Boucher.
The BBC's Rob Watson in Washington says it all comes just as relations between Washington and Tripoli appeared to be warming rapidly following the decision by Libya's leader, Colonel Gaddafi, to dismantle weapons-of-mass-destruction programmes.
Our correspondent says there are signs the US is anxious to keep that warming process going - a White House spokesman was careful to say that continued co-operation from Libya would go hand in hand with better relations with the United States.