An Israeli airstrike on a school sheltering displaced persons in Gaza City killed at least 15 Palestinians on Saturday, hours after two strikes in the occupied West Bank killed nine militants including a local Hamas commander, Hamas said.

The Israeli military said the first of two West Bank airstrikes hit a vehicle in a town near the city of Tulkarm, targeting a militant cell it said was on its way to carry out an attack.

A Hamas statement said one of those killed was a commander of its Tulkarm brigades, while its ally Islamic Jihad claimed the other four men who died in the strike as its fighters.

Hours later, a second airstrike in the area targeted another group of militants who had fired on troops, Israel's military said, during what it described as a counterterrorism operation in Tulkarm.

Palestinian news agency WAFA said four people had died in that strike, and Hamas said all nine of those killed in the two Israeli attacks in the West Bank were fighters.

Violence in the West Bank was on the rise before the Israel-Hamas war in Gaza and has risen since, with frequent Israeli raids in the territory, which is among those that the Palestinians seek for a state.

There has also been an increase in anti-Israeli street attacks by Palestinians.

The latest strikes in the Palestinian territories came amid Israel's growing tensions with Iran and Lebanon's Hezbollah group that have fanned fears of a widened conflict in the Middle East.

The U.S. and international partners including France, Britain, Italy and Egypt, continued diplomatic contacts on Saturday seeking to prevent further regional escalation.

Hamas said it had begun a "broad consultation process" to choose a new leader three days after the assassination in Tehran of Ismail Haniyeh, who was the face of the group's international diplomacy. Iran and Hamas have blamed Israel and vowed to retaliate. Israel has not claimed or denied responsibility.