UN Secretary-General Ban Ki Moon has voiced shock and anger at the "heartbreaking" destruction of Gaza as he toured the devastated region.

He was in the Gaza Strip to pledge aid for Palestinians after Israeli attacks killed 1,300 people and left thousands homeless.

Israel had said it would withdraw its remaining troops before Barack Obama's inauguration as US president, seemingly to avoid clouding the start of a new era in a key alliance.

A ceasefire took hold on Sunday but Hamas has demonstrated it remains in charge in the coastal enclave and held "victory" rallies to coincide with Mr Ban's visit.

Mr Ban said: "I have seen only a fraction of the destruction. This is shocking and alarming. These are heartbreaking scenes I have seen and I am deeply grieved by what I have seen today."

He held a press conference against the backdrop of a UN warehouse which stored food aid and which was still smouldering after it was set ablaze by Israeli gunfire last Thursday.

Gaza's infrastructure has been left in ruins, with a repair bill estimated at about £1.3 billion.

Hamas said 5,000 homes, 16 government buildings and 20 mosques were destroyed and that 20,000 houses were damaged. Israel has said militants hid weapons inside the mosques.

In Geneva, World Health Organisation head Margaret Chan warned of a looming health crisis for many among the 1.5 million Palestinians living in Gaza.

Saudi Arabia has pledged $1 billion (£700,000) for rebuilding and the European Union said the bloc's foreign ministers planned to meet in Brussels to discuss humanitarian aid.

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