The attack happened near the town of Kedumim on Monday, Israeli Army Radio said the military had imposed a cordon around all villages in the area to search for the suspects, who it believes fled to a nearby Palestinian village.
Israeli Prime Minister Benjamin Netanyahu vowed to bring the perpetrators and anyone who aided them to justice.
PM Netanyahu:— Prime Minister of Israel (@IsraeliPM) "We will find the abhorrent murderers and settle accounts with them and with all those who aided them. No one will get away."January 6, 2025
"No one will be spared," he posted on X.
There was no immediate comment from the Palestinian authorities in the West Bank.
Hamas, the militant group which has run the Gaza Strip and has a presence in the West Bank, praised the attacks as a "heroic response against the occupation's continued crimes (including) the war of genocide in Gaza", but did not claim responsibility.
Violence in the West Bank has been spiralling, with hundreds of Palestinians and dozens of Israelis killed since the October 7, 2023, attack by Hamas militants on southern Israel triggered the war in Gaza.
Israel's defence minister Israel Katz said he had instructed the military to "act forcefully" in response to the attacks, and said anyone who followed the path of Hamas in Gaza "will pay a heavy price".
The ambulance service, Magen David Adom, said two women in their 60s and a man about 40 years old were pronounced dead at the scene, while seven passengers were wounded, including a 63-year-old male bus driver who is in serious condition.
Hundreds of thousands of Israelis have settled in the West Bank since Israel captured the territory in a 1967 war.
Most countries consider the settlements illegal, although Israel disputes this, citing historical and biblical ties to the land.
Palestinian security forces moved into Jenin, in the northern West Bank, in December in a move they say is aimed at suppressing armed groups of "outlaws" who have built up a power base in the city and its adjacent refugee camp.
On Sunday, Israeli forces killed a 37-year-old man in a town south of Jenin after opening fire on his home, while a 17-year-old was killed in an Israeli raid in Askar camp in Nablus, according to Palestinian officials.
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