Israeli tanks withdrew from Beit Hanoun in the Gaza Strip after a six-day siege yesterday, revealing the full scale of destruction during a raid in which more than 50 Palestinians and one Israeli soldier were killed.

Palestinian agencies condemned the destruction of homes, orchards, water pipes and electricity cables during the raid, which was intended to curb militant rocket attacks.

Although most of the dead were gunmen, witnesses accused Israeli troops of killing up to 15 civilians, including one man who was shot dead after being interrogated and released with a note granting him safe passage.

When outsiders gained access yesterday they found the town’s historic Nasr mosque almost flattened, except for one minaret. It was a legacy of last week’s two-day stand-off, in which 70 besieged Palestinian gunmen were freed by a Hamas women’s march.

Women queued at water trucks, afraid that the remaining water supply had been contaminated by sewage.

The raid left a residue of bitterness, even as Ismail Haniya, the Palestinian Prime Minister, and President Abbas resumed hitherto fruitless talks to create a national unity government. Karen AbuZayd, the commissioner-general of the United Nations Relief and Works Agency, said her staff had been unable to deliver emergency relief until Saturday, the fourth day. “I think it is reprehensible,” Ms AbuZayd said. “We are here as a humanitarian agency. There are certain laws of war, there are certain things that should be respected.”

Other agencies said they were granted limited access earlier during the week-long operation in the town of 43,000.

Naziq al-Kafarnah, the Mayor of Beit Hanoun, said the town had suffered its worst destruction since the 1967 Six-Day War. He put the cost of damage at $10 million (£5 million).

The Israeli army insisted that its operation had targeted “terrorist organisations and terrorist infrastructure only, while making every effort to avoid harming civilians”.

It said that units “targeted and hit” nine cells that were firing crude, but potentially deadly, Qassam rockets into Israel, killing dozens of armed gunmen. It also uncovered rocket-launchers, anti-tank missile launchers, grenades, explosive devices, Kalashnikov assault rifles, ammunition and observation equipment.

Palestinians protested that Israeli troops held them prisoner in their homes while turning upper floors into snipers’ nests, from one of which an innocent man was killed after being questioned and cleared.

Witnesses said that Mazen Shabat, 25, was released on Saturday from an Israeli interrogation centre in the agricultural college, but was killed by a sniper 20 minutes later as he walked home.

Relatives produced a handwritten Hebrew note found on his body dated November 4, 2006, reading: “Mazen Hani Shabat, ID number 906774211, was in an IDF questioning in the agricultural college. Please do not withhold him. Major Amir.”

Recovering in hospital after surviving the incident, the dead man’s cousin, Zaher Shabat, 32, told The Times: “We passed many different tanks on the way then got to some houses which had snipers, and they weren’t so forgiving so they opened fire on us.”

An Israeli military spokesman said that an initial investigation had proved unable to identify the case, and promised: “We will further investigate.”

Peter Lerner, the Israeli military’s head of co-ordination and liaison, said that it had good working relations with humanitarian groups and blamed “mishaps” on “the failure of the organisations to meet the timetable for entering Beit Hanoun”.

Palestinians said such raids only increased fury at Israel. “Thirty to 40 Israeli soldiers took over our house, defecating in it and terrifying us,” said Sumaya Abu Amsha, 30.

“My son is 4 and has a plastic toy gun. They broke it into pieces in front of him. He started crying and said ‘I wish it was a real gun’. Are they a real army? They are animals.”

Times Recommends

• The Japanese Prime Minister is doomed: or is he?
• Brighton company 'involved in cyber attack'
• The art of survival: it’s all in the mind