The decision to send Prince Harry to Iraq is being reviewed by senior army officers, it has emerged.
Eleven UK troops have died in Iraq this month, and officials fear Harry would be a major terrorist target.
The Ministry of Defence (MoD) said his deployment had always been under "constant consideration" and it remained its intention to send him.
The prince is said to be determined to serve in Iraq, but his friends denied he would quit if he was not sent.
BBC royal correspondent Peter Hunt said Harry's friends admitted he would be "very disappointed" if he could not serve with his unit.
General Sir Richard Dannatt, head of the Army, will have to decide whether to stand by his original decision to sanction Harry's deployment.
But Sir John Nott, Conservative defence secretary during the Falklands War, told BBC Radio 4's The World at One that he was opposed to it.
"The danger is that Prince Harry will be hazarding the lives of other soldiers and young officers and I think that's not right."
Last week two British soldiers died while doing the same job Prince Harry would be expected to do during his six-month tour.
And earlier this month a Challenger tank was seriously damaged in an attack by Iraqi insurgents.
Harry, 22, is currently set to go to Iraq within weeks.
An MoD spokeswoman said: "It is still our intent that Prince Harry will deploy as a troop leader."
Clarence House would not comment on speculation about the prince's deployment.
As an officer, Harry is scheduled to be a troop leader in charge of 11 soldiers carrying out reconnaissance work and gathering intelligence using armoured fighting vehicles.
FATALITIES IN APRIL
23 April Kingsman Alan Jones
19 April Corporal Ben Leaning, Trooper Kristen Turton
15 April Colour Sergeant Mark Powell, RAF Sergeant Mark McLaren
5 April Second Lieutenant Joanna Yorke Dyer, Corporal Kris O'Neill, Private Eleanor Dlugosz, Kingsman Adam James Smith
2 April Rifleman Aaron Lincoln
1 April Kingsman Danny Wilson
In February Clarence House and the MoD confirmed the prince would be deployed to Iraq, saying he would take on a "normal troop commander's role" rather than a desk job.
The BBC's Peter Hunt said: "Harry would struggle with any decision, on the grounds of safety, to change his role and perhaps put him behind a desk in Basra.
"He has always insisted he wanted to serve as an active army officer and not be treated differently because of his status."
BBC defence correspondent Paul Wood said a "truly dreadful" month for British troops in Iraq had made plans for Prince Harry less certain.
"The problem is, it's not just a matter of one young, very brave, very honourable second lieutenant going to do the job they were trained to do."
He added the review would look at whether sending the prince could put others in danger, and the risks of him being kidnapped or becoming a "bomb magnet".
Prime Minister Tony Blair has refused to comment, telling BBC News: "That's a matter for the armed services."
The deployment will make the prince the first royal to be deployed on a tour of duty in a war zone since the Duke of York served in the Falklands conflict in 1982.
Sir John said the issue of Harry's deployment was different from his uncle's because the war in Iraq was "much more fraught".
"There was complete public support for the Falklands campaign, there certainly isn't for Iraq," he said.
"It raises political and constitutional issues. The situation in Iraq is clearly extremely difficult, particularly with armoured cars."
Harry has been taking part in preparation exercises ahead of his deployment.