The youngsters - including at least two under 15 - were shot and injured as they gathered the gravel to sell cement manufacturers struggling to meet a fraction of the demand for building materials still banned from entering Gaza through Israel.

The shootings - highlighted in reports this week by two human rights agencies - are the latest development to come to light in a more general military enforcement of a buffer zone inside Gaza’s border.

The UN says this has resulted in 22 civilian deaths and 146 injuries since the end of Israel's 2008-9 military onslaught on the Hamas-controlled territory. A 91-year-old man and two other civilians were killed last month as they grazed sheep close to the border.

Mohammed Mogah, 16, was shot in his side at what he claims was a range of 700 metres - well beyond the 300-metre border exclusion zone declared in 2008 by the Israeli military.

Showing the scars from the entry and exit wound, he told The Independent he had been sifting sand from a pile of gravel in a cooking sieve, with his back to the border, before loading it onto a donkey cart, when he was hit.