Israeli border police stand guard as Palestinians look on after an attack by three Palestinian assailants at Damascus Gate, a main entrance to Jerusalem's Old City. (Menahem Kahana/AFP/Getty Images)

Three Palestinians armed with automatic rifles, knives and bombs killed an Israeli police officer in the heart of Jerusalem on Wednesday before they were shot dead by police, Israeli officials said.

It was the first time Palestinians appeared to have coordinated an attack against Israeli security forces. Israeli police said it marked a serious escalation in the daily violence that has plagued Israel and the occupied West Bank for more than four months.

Since Oct. 1, 27 Israelis and two foreign citizens have been killed in a series of knife, shooting and vehicular attacks by Palestinians. More than 150 Palestinians have been killed: more than 100 while carrying out the attacks, and the rest during clashes with the Israeli military. Hundreds have been injured on both sides.

One police officer was also critically injured in Wednesday’s shootout, which took place just outside the walls of the Old City.

’A new kind of terrorism in Israel

Israeli police spokeswoman Luba Samri said the two female officers had been on a routine patrol when they spotted two men acting suspiciously. After the officers approached them and asked for identification, one of the men pulled out an automatic rifle and began shooting, Samri said. The two other Palestinian men joined in the attack before being overpowered by additional Israeli forces.

Until now, most acts of violence have tended to be committed by opportunistic lone wolves, usually Palestinian teenagers armed with stones or knives or using cars. Only a handful of the attackers have used guns.

Avishai Peled, deputy commander of the Jerusalem district police, said the use of automatic rifles and explosives was “unprecedented in the current wave of violence and is seen as an escalation.” He said Israel’s Shin Bet security agency would be involved in investigating the attack.

The Palestinian Health Ministry identified the three Palestinian men as Ahmed abu Al-rub, Mohammed Kamil and Ahmed Zakarna, all in their early 20s, from the town of Qabatiya near Jenin. It is unclear whether they were affiliated with a militant Palestinian group.

Israeli police identified the officer who was killed as Hadar Cohen, 19.

Avigdor Lieberman, a hard-line legislator and former Israeli foreign minister, told Israeli TV that Israel must crack down further on the Palestinians to stop the violence, even though Israel has been criticized in international forums as being too harsh in its responses.

The deadly gun battle broke out in the heart of Jerusalem on Wednesday. The three Palestinians assailants were armed with rifles, knives and bombs, Israeli police said. (The Washington Post)

Maj. Gen. Nitsan Alon, head of the Israeli army’s operations directorate, told a gathering of foreign journalists on Wednesday that the violence showed no signs of abating anytime soon and that Israel needs to adapt its response accordingly.

“We are working with the assumption that this wave of terror will be with us at least until the end of 2016,” he said. “But we think it’s important, as part of our counterterrorism measures, to separate between Palestinian terrorism and civilian society. The political echelons have adopted our recommendation not to close the West Bank and allow Palestinians to continue working in Israel.”

On Monday, after a similar shooting attack at a West Bank checkpoint by a Palestinian security officer that left three Israeli soldiers wounded, the Israeli military imposed a partial closure on the nearby Palestinian city of Ramallah. For most of the day, the city, which is the de facto Palestinian capital, was closed to all nonresidents.