JERUSALEM — Israeli police stepped up security measures in Arab neighborhoods of East Jerusalem on Monday, searching trucks and arresting relatives of the Palestinian truck driver who rammed his vehicle into a crowd of Israeli soldiers at a tourist spot.
Four soldiers were killed and 17 others injured in the attack Sunday.
Officials arrested nine people, five of them relatives of 28-year-old Fadi Qunbar, the slain attacker. All those arrested were from the Jabel Mukaber neighborhood of East Jerusalem where Qunbar lived, police said.
Police forces checked drivers and searched parked cars and trucks throughout East Jerusalem in an effort to prevent copycat attacks, police spokesman Micky Rosenfeld said.
An investigation is underway as to how Qunbar managed to make his way on Sunday to the Jerusalem promenade where the soldiers gathered, who owned the truck he drove, and whether he planned his attack ahead of time, Rosenfeld said.
Police used concrete slabs to block some entrances of Jabel Mukaber, and a police officer checked cars leaving it.
Israeli special forces dismantled a mourning tent erected to receive visitors paying respects for Qunbar, who was fatally shot at the scene of the attack. Overnight, police say, Palestinians shot fireworks at Israeli forces at a police post near the neighborhood.
Prime Minister Benjamin Netanyahu said authorities would increase the number of concrete barricades along Jerusalem roads where pedestrians gather, to protect them from similar attacks by vehicles, and that Israeli security agencies are working on ways to detect attackers ahead of time.
‘‘We are under a new kind of attack, the lone attacker that gets inspiration and decides in a moment to act,’’ Netanyahu said.
Mohammed Qunbar, the attacker’s cousin, said Fadi lived a normal life but carried out the attack as a result of Palestinian anger over what is seen as Israeli encroachment at Jerusalem’s most sensitive holy site.
Jews revere it as the Temple Mount, and Muslims call it the Noble Sanctuary and the site of the Al-Aqsa Mosque. It has been a frequent scene of violence in the past, as Palestinians have accused Israel of secretly plotting to take over the site, which Israel denies.
‘‘What happened is a normal thing,’’ Qunbar said of his cousin. ‘‘After all, this is a response to what is happening at Al-Aqsa. He was very connected to Al-Aqsa.’’
The attack was one of the deadliest in more than a year of Israeli-Palestinian violence. Since September 2015, Palestinian attackers have killed 40 Israelis and two visiting Americans in knife attacks, shootings, and assaults using cars to ram into people. During that time, 230 Palestinians have been killed by Israeli fire.
Israel says most of the Palestinians killed over the past 16 months were attackers. The Palestinians and rights groups say Israel has at times used excessive force.
The latest attack came as tensions have been rising in the city after a series of statements by people close to President-elect Donald Trump that he is determined to move the US Embassy to Jerusalem.
The United States, like other countries, keeps its embassy in Tel Aviv, saying the fate of Jerusalem must be decided in negotiations between Israel and the Palestinians.
