Israeli officials say three Israelis died and one more was wounded when a Palestinian broke into a home in a settlement in the occupied West Bank and stabbed its residents while they were eating dinner.
Two of the victims died soon after the attack in the area known as Neve Tsuf, north of Ramallah. Another victim died later in the day.
The assailant was shot by Israeli police and is hospitalized in Israel. He has been identified as 20-year-old Omar al-Abed. His brother also has been arrested.
Elsewhere Friday, three Palestinians died when clashes between Israeli security forces and Palestinians turned violent.
Tensions have been rising for days after Israel installed metal detectors at a site sacred to both Muslims and Jews, after two Israeli police officers were killed there by Arab gunmen.
On Friday, Israel barred Muslim men under the age of 50 from entering the contested Jerusalem holy place for noon prayers
Officials said the clashes at the Old City shrine had been expected.
The site is known as the Noble Sanctuary to Muslims, and as the Temple Mount to Jews. It is the holiest Jewish site and the third holiest in Islam.