Four Israelis were killed inside a synagogue in Jerusalem on Tuesday morning local time, by two Palestinians armed with a gun and a meat clear, reports Reuters.
Eight other people are believed to have been injured. The attackers, named as Ghassan Abu Jamal and Uday Abu Jamal, are reported to be members of the Popular Front for the Liberation of Palestine, were shot dead by police.
According to The Guardian, the PFLP praised the killing however, did not claim responsibility for it.
Israeli police said three of those killed held dual US and Israeli citizenship - Aryeh Kupinsky, Cary William Levine, and Mosheh Twersky. The fourth person held dual British and Israeli citizenship - Avraham Goldberg.
The attack took place inside the ultra-orthodox region of West Jerusalem.
The attack has been condemned by the Palestinian president Mahmoud Abbas, and the Israeli Prime Minister Benjamin Netanyahu who has vowed to respond with a "heavy hand".