A Palestinian teenager was shot dead and another wounded by Israeli troops during a raid in the northern West Bank, Palestinian medical sources said.
The Israeli military said its soldiers fired at an armed man on a rooftop and another who had thrown a bomb.
Amir Basyuni, 15, was shot in the neck when he went onto the roof of his home during the operation in the Ain Beit al-Ma refugee camp near Nablus.
A second Palestinian, aged 18, was also shot and wounded during the raid.
"Our soldiers were conducting an arrest operation in Nablus. They saw and armed man on a roof, opened fire against him and identified a hit," an Israeli army spokesman told the AFP news agency.
"Soldiers also saw a Palestinian who threw an explosive device at them. He was shot and wounded, then evacuated by the Palestinians."
Israeli forces arrested eight Palestinians from Ain Beit al-Ma camp and the nearby Balata camp before withdrawing.
In a separate development, Palestinian militants have fired rockets from the Gaza Strip into an Israeli coastal area near the city of Ashkelon.
They landed in fields and an industrial zone. Officials said nobody was injured.
The Israeli army fired back, using artillery.
A faction of the Palestinian group, Islamic Jihad, said it was responsible for the attacks.
On Wednesday a senior figure in the group, Khalid al-Dahdooh, was killed in an explosion in Gaza City.
US aid returned
Meanwhile, the Palestinian Authority returned a lump sum of unspent aid it received from the US, a US official said on Thursday.
Assistant Secretary of State for Near Eastern Affairs David Welch told Congress that the PA had returned about $30m of the $50m of American aid on Wednesday.
The rest will be returned before the militant group, Hamas, takes over in government.
Washington considers Hamas to be a terrorist organisation and had asked for the money back last month.
Mr Welch said Washington would not provide assistance to Hamas, whether it was in or out of government, if it did not renounce violence and recognise Israel.
But he did say some money would probably be redirected to humanitarian projects not funded directly through the government.
"Because it serves important US national interests, we are looking for ways to help the Palestinian people, particularly through provision of assistance to help meet basic humanitarian needs," he said.