"No stone will be left unturned" in the inquiry into photos allegedly showing UK troops abusing an Iraqi, the armed forces minister has promised MPs.
The Daily Mirror insists the photos are genuine
In a Commons statement, Adam Ingram said the Daily Mirror newspaper had handed over 20 photos of alleged abuse.
The photos, published this weekend, appear to show a hooded and bound Iraqi prisoner being mistreated.
Some military personnel have questioned their authenticity, but the newspaper insists they are genuine.
The chairman of the Commons defence select committee is proposing to call Mirror editor Piers Morgan for questioning about the pictures.
Labour MP Bruce George says there is "intense interest" in the story and a questions session might "clear the air". MPs are asking whether the Mirror offered to pay for such photos.
IRAQ TROOP INQUIRIES
33 cases of civilian deaths, injuries or ill-treatment caused by UK troops have been investigated
12 of the cases are on-going, the other 21 are completed
Of the finished inquiries, there was "no case to answer" in 15 cases. Recommendations in the other six cases are still being considered
The Royal Military Police are investigating in the UK, in the southern Iraqi city of Basra and in Cyprus, where the regiment in question - the Queen's Lancashire Regiment - is based.
Mr Ingram said "any decent thinking person" would be disturbed by the photos.
"From the outset, we have taken the allegations seriously and taken the photos at face value and will continue to do so unless there is evidence to the contrary," he said.
If soldiers were found to have acted
unlawfully then appropriate action would follow, he said.
But it would be wrong to speculate about the outcome of the investigation.
Mr Ingram added: "While treating these allegations with full seriousness,
we should not allow them to colour our judgment of the quality or integrity of
our troops or of the Army as a whole."
The minister rejected suggestions that Ministry of Defence inquiries into other claims about mistreatment of Iraqi prisoners and civilians, some resulting in deaths, were "unduly long".
His statement follows demands from the Conservatives and Liberal Democrats to address MPs on the issue.
Shadow defence secretary Nicholas Soames called the allegations "extremely
serious" and said they should be thoroughly and swiftly investigated.
"They are the more shocking because of the outstanding reputation of the
British armed forces," said Mr Soames.
Earlier, Lib Dem leader Charles Kennedy said the pictures - showing the prisoner being struck with a rifle butt,
being urinated on and having a gun held to his head - would have a "massive impact" across Iraq and the Arab world, even if they were fake.
The prime minister has already said that, if genuine, the abuse would be "completely and totally unacceptable".
Sources close to the regiment insist the photographs are not genuine.
Their suspicions focus on the troops' clothing, weaponry and equipment, the quality of the photos, and the lack of sweat, dirt or injuries on the body of the alleged victim.
The newspaper says the sources for its photos are two members of the regiment who are standing by their account of what happened.
'Tip of the iceberg'
The two said the images represented only the tip of the iceberg.
One said: "Maybe the officers don't know what is going on - but everybody else does. I have seen literally hundreds of pictures. The Army knows a lot more has happened."
Many people believe that regardless of whether the photographs are genuine or not, the damage caused by their publication cannot be overestimated.
Former Queen's Lancashire regiment commander Colonel David Black, who believes the pictures are fakes, said: "Hopefully, if we get an investigation through quickly, the regiment will at least have the satisfaction of having its name cleared.
"But the damage done to the British and Coalition policy in Iraq is irreparable," he told BBC News.