World Bulletin / News Desk
According to a police statement, the attacker was "neutralized" by an officer in the area.
The injured guard was taken to a hospital, it added.
According to Israeli Channel 10, an Israeli man in his 20s was fatally injured after he was stabbed multiple times on his upper body in the Old City of Jerusalem.
Later on Sunday, Israeli newspaper Yediot Ahronot said on its website that the security guard lost his life in the hospital in Western Jerusalem.
Israeli and Palestinian officials have not made a statement over the identity of the attacker.
According to the Yediot Ahronot, the attacker was 28-year-old Abdurrahman Beni Fazil from the occupied West Bank.