JERUSALEM, Dec 4 (Reuters) - A Palestinian stabbed an Israeli outside Jerusalem"s walled Old City on Saturday before he was shot and killed by security forces at the scene, police said. A video released by Israeli police appears to show a man crossing a street and then turning around and several times stabbing or attempting to stab an ultra-Orthodox Jewish man who had been walking behind him. The assailant then runs toward a border policeman and is shot several times by him and another officer as he falls to the ground - all in the space of 50 seconds. Another video circulating on social media appears to show the last few seconds of the incident, in which one of the officers continues to shoot at the assailant at least twice when he is already lying on the ground. Reuters could not independently verify the footage. The chief of Israel"s border police Amir Cohen said the officers had acted correctly. Palestinian officials condemned the assailant"s death and said it amounted to an execution. "The killing of the young man after he had been wounded is a documented war crime," Palestinian President Mahmoud Abbas said the statement. Israeli Prime Minister Naftali Bennett backed the officers, who he said "acted very quickly and decisively, as expected of Israeli police, against a terrorist who tried to murder an Israeli citizen". The Israeli stabbed was moderately wounded, Israel"s ambulance service said. Palestinian stabbing attacks against Israelis, many carried out by assailants with no known affiliation to militant groups, have occurred sporadically since 2015, a year after Israeli-Palestinian peace talks collapsed. Palestinians want the eastern part of Jerusalem as capital of a future state. Israel captured that territory, including the Old City, in the 1967 Middle East war and annexed it in a move not recognised internationally. Israel says the entire city is its eternal and indivisible capital.