Israeli troops have killed a 10-year-old boy during a raid into central Gaza, Palestinian medics say.
Israeli military officials said troops responded when a group of Palestinians opened fire on them, and only gunmen were identified as having been hit.
An armed Palestinian was also shot dead by Israeli troops while trying to plant a bomb near the Israeli border.
The violence came as Palestinian and Israeli leaders met in Jerusalem to try to promote progress to a peace deal.
Palestinian Authority President Mahmoud Abbas and Israeli Prime Minister Ehud Olmert were reviewing peace negotiations nearly three months after they were launched at a US-hosted conference.
Correspondents say the negotiations appear to be stalled as violence has been on the rise in Gaza.
The child, identified as Tamer Abu Shaar, was reportedly hit in the head by an Israeli bullet during an incursion near the town of Deir al-Balah.
The armed wing of the militant Hamas said it had fired 13 mortar rounds at an Israeli foot patrol in the area.
The militant group Democratic Front for the Liberation of Palestine said one of its members was killed in an exchange of fire near the Gaza-Israel border fence.
Urgency call
Palestinian Prime Minister Salam Fayyad told visiting US-Jewish leaders that not enough progress had been made in negotiations and the pace must pick up significantly if a treaty is to be agreed this year.
His government holds sway only in the Israeli-occupied West Bank, while Hamas has been the de-facto ruler of the Gaza Strip since seizing it last June. Hamas rejects Israel's legitimacy and is shunned by Israel.
Israeli Foreign Minister Tzipi Livni has also warned that time is not on Israel's side when it comes to finding a solution.
"Whoever thinks stopping negotiations will stop terror is not in touch with reality," Ms Livni said.
But she also said it was not Israel's job to solve the Palestinian refugee problem, and any future Palestinian state would have "to run through Israeli security".
Separately, Israeli human rights group B'tselem said Israel had imposed severe new restrictions on the movement of Palestinians in the West Bank over the past two weeks.
The group said the Israeli army had erected many new roadblocks, cutting off northern parts of the West Bank and disrupting daily life for tens of thousands of people.
Three days ago, the United Nations humanitarian chief, John Holmes, urged Israel to relax the closures, saying they increased poverty, unemployment and reliance on aid.
Israel said the measures were necessary for security reasons.
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