A senior official with the UN Mine Action Service (UNMAS) has said there are some 37 million tonnes of debris to clear away in Gaza once the Israeli offensive is over, AFP reports.

And unexploded ordnance buried in the rubble would complicate that work, said UNMAS’ Pehr Lodhammar, who has run mine programmes in countries such as Iraq.

It was impossible to say how much of the ammunition fired in Gaza remained live, said Lodhammar.

“We know that typically there is a failure rate of at least 10 per cent of land service ammunition,” he told journalists in Geneva.

“What we do know is that we estimated 37m tonnes of debris, which is approximately 300 kilos of debris per square metre,” he added.

Starting from a hypothetical number of 100 trucks, that would take 14 years to clear away, he said.