An obscure Palestinian group claimed responsibility on Monday for a truck ramming in Jerusalem that killed four Israeli soldiers, an attack that Israeli Prime Minister Benjamin Netanyahu said earlier was likely inspired by Islamic State.
A female army officer and three officer cadets who were killed in Sunday's incident were buried on Monday.
Seventeen other people were injured when the truck barrelled into a group of Israeli soldiers. The Palestinian driver was shot dead in the attack.
"We know the identity of the attacker. According to all the signs he is a supporter of Islamic State," Mr Netanyahu said.
The attack, however, was claimed by the "Groups of Martyr Baha Eleyan" in a post on Arabic social media.
The organisation said it was formed by Palestinians who "have no links outside Palestine". It said it had acted previously, giving no details, and threatened more attacks.
"This is not the first operation executed by our groups and it will be followed by a flood of distinctive operations in defence of our Jerusalem and in revenge of our martyrs and prisoners," its statement said.
The group has not been heard of previously and Reuters was unable to authenticate the validity of the claim.
Iraq and Syria are the strongholds of Islamic State (IS) militants although the jihadist group has taken responsibility for deadly attacks in many countries around the world.
However, actions inspired by Islamic State in Israel, the Israeli-occupied West Bank and in Jerusalem have been rare and only a few dozen Arab Israelis and Palestinians are known to have declared their sympathy with IS.
Mr Netanyahu visited some of the injured in hospital on Monday and said Israel needed to prepare to face a different threat.
"I think the most important thing we need to understand is that we are under a new kind of attack. An attack by a lone assailant who is inspired, and on the spur of the moment decides to act, in this case, a ramming attack," he told reporters.
He said extra security steps were being taken, such as adding physical barriers in public places, intensifying intelligence efforts to help identify and track potential assailants, and raising the vigilance of security forces.
A wave of Palestinian street attacks on Israelis, including vehicle rammings, has largely slowed but not stopped completely since it began in October 2015. Thirty-seven Israelis and two visiting Americans have been killed in those assaults.
During the same period, at least 231 Palestinians have been killed in violence in Israel, the West Bank and Gaza Strip.