JERUSALEM - A prominent Palestinian human rights group says it has found evidence that 68 children were killed in the Gaza Strip in the 12 months to June this year as a result of "disproportionate and excessive lethal force" by the Israeli military.

The deaths are documented, with witness testimony, in a report published today by the Palestinian Centre for Human Rights. Many of the deaths resulted from an Israeli military incursion into Jabaliya, in eastern Gaza, in late February and early March, in which more than 100 Palestinians, at least half of them civilians, died in what Israel said was an operation to stop rockets being fired into southern Israeli towns.

Others were killed in smaller strikes before a ceasefire was reached in June between Gaza's Hamas administration and Israel. Despite occasional breaches, the truce still holds. In the year to June, another 12 children were killed by Israeli troops in the West Bank.

The rights group said many of the deaths passed without investigation, and those internal Israeli military inquiries that were held did not meet international standards of independence and transparency.

Since the start of the second intifada in late 2000, around 4,800 Palestinians have been killed by the Israeli military, including nearly 900 children. More than 1,000 Israelis have been killed, including around 120 children.

The centre cited as one example an incident in April near the village of Juhor al-Dik, when a Reuters cameraman was killed by Israeli tank fire. The same tank shells killed two children: Ahmed Aaref Farajallah, 14, and Ghassan Abu Otaiwi, 17. The Israeli military said it investigated the incident and concluded that the tank crew reached a "reasonable conclusion" that the Palestinians gathered on the road were "hostile", and said the decision to fire was "sound".

The Israeli military did not respond to the criticisms last night, because of a Jewish religious holiday. However, it has in the past repeatedly defended its military actions in Gaza, saying it does not intentionally target civilians, and noting that Palestinian militants frequently fire from civilian areas.

The centre said the killing of unarmed civilians represented grave human rights violations, and called on Israel to establish an independent commission to investigate the deaths. It condemned Palestinian militant groups that recruited children to fight and said militants should not fire missiles from in or around residential areas.