Israeli army chief of operations Giora Eiland said an internal investigation showed that "the shots were apparently fired by Israeli soldiers from the outpost at Netzarim".

"This was a grave incident, an event we are all sorry about," he told Israeli radio.

The deputy army chief of staff, Major-General Moshe Yaalon, called the boy's death "heartrending", but accused the Palestinians of making "cynical use" of children in clashes with Israeli troops.

'Criminals'

For 45 minutes, Muhammad and his father sought sanctuary in vain behind a small metal barrel as bullets rained around them.

From his hospital bed in Jordan where he underwent surgery to remove bullets from his arm and pelvis, he gave his first reaction to the killing of his son.

"I appeal to the entire world, to all those who have seen this crime to act and help me avenge my son's death and to put on trial Israel.

"I also plan to take Israel to the international courts and ask that the criminals responsible for the death of my son be punished," he said.

'Worst nightmare'

Recounting what he remembered of the incident, he said he had done all he could to protect his son.

"It is the worst nightmare of my life... My son was terrified, he pleaded with me: 'For the love of God protect me, Baba (Dad).

"I will never forget these words."

Mr Durrah said the Israeli troops had fired relentlessly, even shooting at an ambulance that had tried to rescue him and his son.

Its driver was also killed in the incident, and a second ambulance driver was wounded.

Doctors say Mr Durrah will suffer permanent paralysis in his right hand.