After the latest attacks in a nearly two-month wave of violence, an Israeli woman was in critical condition, while the other two assaults did not cause serious injuries.
The attacks came after the violence had shown signs of subsiding last week before a new series of assaults took place on Thursday.
Amid international efforts to restore calm, US Secretary of State John Kerry is to travel to Israel and the West Bank to meet Prime Minister Benjamin Netanyahu and Palestinian president Mahmud Abbas on Tuesday.
"This is not terrorism by organisations," he said at the start of a cabinet meeting.
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"This is terrorism by individuals, occasionally with kitchen knives, who are incited mainly by social media. It is very difficult to hermetically prevent the arrival of such knife-wielding, or other, terrorists to this or that place."
He said "citizens must be on maximum alert".
Today's first attack saw a 16-year-old Palestinian girl who tried to stab an Israeli civilian run over by a Jewish settler and then shot dead by soldiers.
Palestinian security officials confirmed the alleged attacker had died of her wounds and identified her as Asheraqat Qatanani from Askar refugee camp near Nablus.
A Jewish settler in the area, Gershon Mesika, told army radio he hit the assailant with his car before a soldier shot her.
Later, a Palestinian driving a taxi tried to run over civilians and then charged at them with a knife before a civilian shot him dead, police said.
The statement provided no further details on the civilian. A hospital spokeswoman said a 51-year-old Israeli was lightly injured when hit by the taxi.
Israeli media reports said the woman was aged around 20, but there was no official confirmation of this. Israel's Shin Bet security agency identified the attacker as Issam Thawabteh, 34, from Beit Fajjar near Bethlehem.