Israeli forces hit the city of Jenin with drone strikes during an overnight operation on Monday that left at least seven people dead.
The Palestinian health ministry confirmed at least seven people had been killed and 27 wounded in Jenin, while another man was killed in the city of Ramallah after being shot in the head at a checkpoint.
As daylight broke on Monday, thick black smoke from burning tyres set alight by residents swirled through the Jenin streets while calls to support the fighters rang out from loudspeakers.
A spokesman for Palestinian President Mahmoud Abbas called the operation "a new war crime against our defenceless people".
The Israeli military said the targeted building functioned as an "advanced observation and reconnaissance centre" and a weapons and explosives site as well as a coordination and communications hub.
It provided an aerial photograph showing what it said was the target and which indicated the building hit was near two schools and a medical centre.
A spokesman said it would last as long as needed and officials suggested forces could remain for days. "An operation doesn't end in one day," Energy Minister Israel Katz, a member of the security cabinet, told Army radio.
Israeli Defence Minister Yoav Gallant said his forces were "closely monitoring the conduct of our enemies...The defence establishment is ready for all scenarios."
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