London in July launched a formal inquiry into the British role in the Iraq war from the planning stages in 2001 to the end of their combat operations in 2009.
The highlight of the inquiry came in January when former Prime Minister Tony Blair faced six hours of questioning before the inquiry. Blair told the panel he made no distinction between disarming Iraq and regime change.
John Chilcot, the head of the London inquiry, said he would consider calling on U.S. servicemen and members of the Bush administration in for formal meetings.
"These could include veterans from the Iraq campaign and officials from the former American administration. We also hope to visit Iraq later in the year," he said. "We cannot take formal evidence as such from foreign nationals, but we can of course have discussions with them."
Prime Minister Gordon Brown, who formally backed the inquiry in 2009, is expected to testify before the panel sometime in March.
Brown and his top Cabinet officials were not expected to appear before June elections.
Chilcot in his summary of the proceedings thus far said the inquiry "has broken new ground and a great deal has been achieved since the launch at the end of July and we aim to complete our report by the end of the year."
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend
'Happy' fan videos make Pharrell cry [VIDEO]