Israel launched air strikes on Gaza Friday in response to militant rocket fire from the Palestinian enclave, as tensions rose following the deadliest army raid on the occupied West Bank in years.
Israel said it had carried out at least two rounds of strikes targeting Hamas Islamists, following waves of rocket launches towards southern Israel.
There were no reported injuries on either side and most of the Gaza rockets were intercepted by Israel's air defence system.
No Palestinian group in Gaza has claimed responsibility for the rockets, but both Hamas and Islamic Jihad had vowed to respond to Thursday's Israeli raid in the West Bank, which killed nine people.
Another Palestinian was killed Thursday by Israeli fire in separate West Bank unrest near Ramallah.
The bloodiest day in the West Bank in years erupted during a raid on the crowded refugee camp in the northern city of Jenin, where gunshots rang through the streets and smoke billowed from burning barricades.
The military said Israeli forces came under fire during a "counterterrorism operation to apprehend an Islamic Jihad terror squad" and shot several enemy combatants.
Since its records began in 2005, the United Nations has never logged such a high death toll in a single operation in the West Bank.
The violence prompted the Palestinian Authority to announce it was cutting security coordination with Israel, a move criticised by the United States.
Among those confirmed dead in Jenin was Majeda Obeid, 61, who lived some metres from the house targeted by the Israeli forces.
Her daughter, Kefiyat Obeid, told AFP her mother was shot as she peered out her window at the clashes.
"After she finished her prayers, she stopped for a moment to look and, as she stood up, she was hit in the neck by a bullet and she fell against the wall and then to the floor," the 26-year-old told AFP, as bloodstains soaked into the rug of their home.
State of panic
The military said the incursion targeted Islamic Jihad militants who were allegedly behind attacks on Israeli soldiers and civilians and, according to Israeli Defence Minister Yoav Gallant, were planning "to conduct a terror attack in Israel".
Three Palestinians were shot in a firefight, while Israeli forces shot a further two "fleeing the scene", an army statement said. Israeli forces also shot a sixth suspect inside a building, and other Palestinians were hit after firing on troops, the army said.
There were no casualties among the Israeli forces, the military said.
Wisam Bakr, director of the Jenin Government Hospital, said there was a "state of panic" in the paediatric ward, with some children suffering from tear gas inhalation.
The Israeli military told AFP "the activity was not far away from the hospital, and it is possible some tear gas entered through an open window".
Jenin resident Umm Youssef Al-Sawalmi said homes were hit during the raid. "Windows, doors, walls and even the refrigerator, everything was damaged by the bullets," she told AFP.
Islamic Jihad spokesman Tariq Salmi vowed that "the resistance is everywhere and ready and willing for the next confrontation".
The latest deaths bring the number of Palestinians killed in the West Bank so far this year to 30, including fighters and civilians, most of whom were shot by Israeli forces.
Saleh al-Arouri, deputy leader of Hamas, which rules Gaza, vowed that Israel "will pay the price for the Jenin massacre".
Bloody massacre
Washington earlier Thursday announced US Secretary of State Antony Blinken would travel next week to Israel and the Palestinian territories, where he will push for an "end to the cycle of violence".
US regional allies Jordan, Qatar and Saudi Arabia all strongly condemned the deadly Israeli incursion.
The mounting toll follows the deadliest year in the Palestinian territory recorded by the UN.
At least 26 Israelis and 200 Palestinians were killed across Israel and the Palestinian territories in 2022, the majority in the West Bank, according to an AFP tally from official sources.
UN peace envoy Tor Wennesland said he was "deeply alarmed and saddened by the continuing cycle of violence in the occupied West Bank".
Thousands flocked to funerals in Jenin, as the Palestinian presidency announced three days of mourning. It charged that Thursday's raid was happening "under international silence".
