Described as the deadliest air strike in over two decades in the West Bank, the Israeli army said the raid in Tulkarem had succeeded in killing "at least seven terrorists", including a Hamas leader and an Islamic Jihad member, who were discussing an "imminent terror plan".

The United Nations Human Rights Office slammed the strike, calling it "unlawful".

"The strike is part of a highly concerning pattern of unlawful use of force by ISF (Israeli security forces) during military-like operations in the West Bank that have caused widespread harm to Palestinians," the UN rights office said in a statement.

"The levelling of an entire building filled with people via aerial bombing shows flagrant disregard for Israel's obligations."

On Friday, hundreds gathered for a public funeral in Tulkarem, where the bodies of the dead were carried through the streets as people waved flags and fired guns into the air.

Several armed fighters, masked and dressed in black, attended the funeral, an AFP journalist reported.

"We hope that all Palestinian people will join hands, as we have one cause," Nasser Kharyoush, a father of one of the victims of the raid, told AFP.

Tulkarem was one of the towns and Palestinian refugee camps targeted during a large-scale Israeli military operation in late August against militants based in the West Bank.

Violence in the West Bank has surged alongside the war in Gaza which began after Hamas attacked Israel on October 7.

Since the Hamas attack, Israeli troops or settlers have killed at least 701 Palestinians in the West Bank, according to the Palestinian health ministry.

At least 24 Israelis, including members of the security forces, have been killed in Palestinian militant attacks during the same period, Israeli officials say.

The United Nations rights office said Thursday's strike came when there were "no clashes or confrontations" at the site.

"The air strike completely destroyed the targeted building and also damaged nearby houses," it said.

"More fatalities may be trapped under the rubble, but recovery and identification are proving difficult in light of the massive impact of the blast."

Major Israeli operations in the West Bank are sometimes occurring "at a scale not witnessed in the last two decades," United Nations human rights chief Volker Turk said last month.

Israel has occupied the West Bank since 1967, and its forces regularly make incursions into Palestinian communities.

But the current raids as well as comments by Israeli officials mark an escalation.