A Palestinian sneaked into an Israeli settlement Thursday and stabbed three people, one fatally.
One Israeli report says other settlers shot and killed the Palestinian who the army calls a terrorist.
One of the victims later died at a hospital. One other was seriously wounded and a third was slightly injured.
The Israeli army said the incident took place in the Adam settlement, between Jerusalem and the Palestinian town of Ramallah in the West Bank.
Violence between Israelis and Palestinians has flared up since March when Palestinians began daily protests along the Israeli-Gaza border.
At least 140 Palestinians and one Israeli soldier have died. Militants in Hamas-ruled Gaza have fired rockets into Israel, prompting a harsh Israeli response.