JERUSALEM — A Palestinian fatally stabbed two Israelis as they walked in Jerusalem’s Old City and seriously injured a toddler and a woman, before he was shot and killed by an officer on duty, police said Saturday in the latest in a series of Palestinian attacks. Jerusalem police chief Moshe Edri said the Palestinian “stabbed an Israeli man, his wife and the toddler” multiple times in an alleyway before stabbing another man. Police Spokeswoman Luba Samri said the Palestinian attacker took a gun from one of the wounded men and opened fire at police and tourists. The Palestinian was then shot and killed by an Israeli police officer who rushed to the scene. A Palestinian security official said seven members of the Islamic militant group Hamas were arrested. Tensions have flared between Israelis and Palestinians in recent weeks, with much of the unrest focused on Jerusalem’s most sensitive holy site, known to Jews as the Temple Mount and to Muslims as the Noble Sanctuary, site of the Al-Aqsa mosque.