At least four Palestinians from the same family have been killed, and 43 people were injured, in the Gaza Strip after Israeli military ordnance left over from last summer's 50-day war exploded, a Palestinian health official has said.

Ashraf al-Qidra, a Gaza health ministry spokesman, said on Thursday that the rocket exploded as Palestinian workers were helping family members remove rubble from a house destroyed in the war between Israel and Hamas, who rule the coastal territory.

The rocket is believed to have been dropped in an airstrike on the house during the war.

Last year, six people, including a video journalist from the AP news agency and his Palestinian translator, were killed as Gaza police engineers tried to defuse unexploded Israeli ordnance.

On Wednesday, Hamas warned of renewed violence unless Israel lifts its blockade of Gaza, at a ceremony marking the end of a military-style summer camp for 25,000 Gazans.

"Today, our message to the occupier is very clear: We will not accept a blockade," said Mahmud Zahar, a senior Hamas leader who has been holding indirect contacts with Israel over a long-term truce in return for an end to the nine-year-old blockade.


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"Break the siege because we will not be able to hold back those who want to defend their territory from those who have destroyed their homes and killed their children," he said.

The Ezzedine al-Qassam Brigades, Hamas's military wing, said participants at the summer camp spent two weeks being "trained in military techniques and in firing live ammunition" as well as "first aid and rescue techniques".

Hamas has long run summer camps in Gaza devoted to sport and the study of the Quran, but over the winter the brigades started giving military training to 15- to 20-year-olds.

Human rights activists had condemned it as a violation of children's rights, but the brigades repeated the exercise with the summer camp, while also raising the upper age limit to 60.

Moatassem, a 15-year-old, said he took part to be able to help defend Gaza.
 
"We will grow up and be able to defend ourselves and our people," he said.

Israel's 50-day war on Gaza in July-August 2014 killed about 2,200 Palestinians and 73 on the Israeli side, destroying or damaging tens of thousands of homes in the impoverished coastal territory.

Source: Al Jazeera And AFP