The Gaza Strip was struck by Israeli missile strikes overnight on Friday in supposed retaliation to two rockets fired by Palestinian armed groups.
The further escalation of tensions comes after one of the worst days of Israeli violence in the occupied West Bank in years killed at least nine Palestinians Thursday.
The rockets fired from Gaza overnight set off alarms in Israeli communities near the border with the southern coastal strip controlled by Hamas but there were no reports of casualties.
The cross-border fire came after an Israeli raid on a refugee camp in the West Bank on Thursday that killed at least nine Palestinians, including militant gunmen and at least two civilians, the highest single-day death toll in years.
Another man died in a separate incident in al-Ramm outside Jerusalem, bringing the Palestinian death toll so far in 2023 to at least 30.
The raid, the latest in a near-daily series of clashes in the West Bank over the past year, came days before U.S. Secretary of State Antony Blinken was due to visit Israel and the West Bank.
Palestinian officials said CIA Director William Burns, who was visiting Israel and the West Bank on a trip arranged before the latest violence, would meet Palestinian President Mahmoud Abbas on Saturday. No comment was immediately available from U.S. officials in Jerusalem.
The months of violence, which surged after a spate of lethal attacks in Israel last year, have drawn fears the already unpredictable conflict could spiral out of control, triggering a broader confrontation between Palestinians and Israel.
The U.S. State Department issued a statement Thursday saying it was "deeply concerned" with the violence in the West Bank and urged both sides to de-escalate the conflict.
The United Nations, Egypt and Qatar have also urged calm, Palestinian officials said.
In Gaza, large rallies were planned for the afternoon following Friday prayers as residents inured to years of exchanges of rockets and airstrikes between Israel and Hamas feared further clashes.
"We didn't sleep the whole night, bombing and missiles," said 50-year-old Abdallah al-Husary. "There is worry and there is fear, any minute a war can happen. With any clash in the West Bank, there can be war along the borders in Gaza."
In the aftermath of Thursday's raid, the Palestinian Authority, which has limited governing powers in the West Bank, said it was suspending a security cooperation arrangement with Israel that is widely credited with helping to keep order in the territory and preventing attacks against Israel.
Prime Minister Benjamin Netanyahu, who returned to power this year at the head of one of the most right-wing governments in Israel's history, said Israel was not looking to escalate the situation, although he ordered security forces to be on alert.
The Israeli Defence Force (IDF) said Friday's air strikes in Gaza targeted an underground rocket manufacturing site and a military base used by Hamas.