Prince William has expressed his sadness after a "close friend" from Sandhurst was killed in Iraq.
Prince William was a contemporary of 2nd Lt Yorke Dyer at Sandhurst
The prince was "deeply saddened" by the death of 2nd Lt Joanna Yorke Dyer, 24, a statement from Clarence House said.
Cpl Kris O'Neill, Private Eleanor Dlugosz and Kingsman Adam James Smith also died in the roadside bomb blast near Basra, southern Iraq on Thursday.
A civilian Kuwaiti translator was also killed in the blast, while a fifth soldier was very seriously injured.
'Thoughts and prayers'
The injured soldier is being treated in the military hospital in Basra.
The statement from Clarence House said Prince William was "deeply saddened to hear the tragic news of Joanna Dyer's death".
It added: "Jo was a close friend of his at Sandhurst and he is very much thinking of her family and friends right now and they will remain in his thoughts and prayers."
Second Lt Yorke Dyer was from the Intelligence Corps attached to the 2nd Battalion The Duke of Lancaster's Regiment.
She was born in 1983 in Berlin and read philosophy, politics and economics at Oxford before officer training at Sandhurst.
Her Commanding Officer, Lieutenant Colonel Mark Kenyon, said: "From a very early stage it was evident that Jo was a talented and energetic officer who was determined to make the most of her deployment to Iraq.
"Her enthusiasm was boundless and her contribution to our operations, even within a few short weeks, was invaluable. We very quickly came to think of her as one of us."
The MoD said: "An enthusiastic and charming officer, Jo quickly made her mark in a communications role with the battalion, a post normally reserved for a more experienced officer."
'Experienced and confident'
Private Dlugosz, 19, from Southampton, who served in the Royal Army Medical Corps, was "held in high regard by all who knew her", the MoD said.
Her troop commander, 2nd Lieutenant Vinny Ramshaw, said: "Pte Dlugosz was a strong and morally courageous young woman, who was an example to many older and more experienced soldiers.
"Supremely dedicated to her work, she thoroughly enjoyed her soldiering and was keen to use her life-saving skills as a medic to help others."
Also from the Royal Army Medical Corps, Cpl O'Neill, 27, from Catterick, Yorkshire, was an "experienced and confident medic, with an unflappable nature", the MoD said.
He was "a committed family man with two small boys", it added.
His squadron commander, Major Phil Carter, said: "I could always depend on Cpl O'Neill."
Kingsman Smith was from 2nd Battalion The Duke of Lancaster's Regiment.
Aged 19 and from Liverpool, he was a "popular and highly respected colleague", the Ministry of Defence said.
Kingsman Smith's commanding officer, Lieutenant Colonel Mark Kenyon, said: "He showed all the qualities of a reconnaissance soldier, dependable, determined and a real team player."
His family released a statement tonight, saying: "Adam was the most wonderful and beautiful person anyone could wish to meet. He always had a smile on his face and loved life so much, he had everything to live for.
"He was a loving son, brother and the best boyfriend in the whole world and he will be missed more than words can say. He will forever be in our hearts."
According to the MoD, the incident happened in the early hours of Thursday as the troops returned from patrol duty.
Their vehicle first came under attack near the centre of Basra and continued on its way.
However, on a stretch of highway in the Hayaniyah district on the north-western outskirts of Basra it was hit by a massive bomb explosion which wrecked the vehicle and left a three-foot crater.
The soldiers were all on patrol in a Warrior armoured vehicle when they died.
This latest incident brings the total number of UK troops killed in operations in Iraq to 140.
Four British servicewomen have now died in action in Iraq, while the death of a fifth was not thought to be combat-related.