Jerusalem (AFP) - Palestinian militant factions on Saturday dismissed a claim by the Islamic State group that it was behind the fatal stabbing of an Israeli policewoman in Jerusalem, saying the assailants came from their ranks.

The Israeli security services also raised doubts about the veracity of the IS claim -- its first for an attack in Jerusalem or inside Israel -- which came with the jihadists facing defeat in their Iraq and Syria bastions.

Three Palestinians attacked officers just outside the walled Old City in annexed east Jerusalem late on Friday before being shot dead by security forces, Israeli police said.

In an online statement, IS said jihadist fighters had targeted a "gathering of Jews", warning that "this attack will not be the last".

But Hamas, the Palestinian Islamist group that runs the Gaza Strip, dismissed the claim, saying the attackers had come from among its own ranks and those of the leftist Popular Front for the Liberation of Palestine (PFLP).

The assault took place as tens of thousands of Palestinians held night prayers at the nearby Al-Aqsa mosque compound, Islam's third-holiest site, on the third Friday of the holy fasting month of Ramadan.

According to police, two assailants opened fire on a group of officers who returned fire, and a third stabbed the border policewoman a short distance away before being shot.

Policewoman Hadas Malka, a 23-year-old staff sergeant major, was taken to hospital in critical condition and later died of her wounds.

- 'Muddy the waters' -

In its statement, IS said the attack was "revenge for the religion of Allah and the sanctities of the violated Muslims".

Hamas spokesman Sami Abu Zuhri said the IS claim was an attempt to "muddy the waters", adding that the attack was carried out by "two Palestinians from the PFLP and a third from Hamas".

The killing was "a natural response to the crimes of the occupier," he said.

A spokesman for Israel's Shin Bet internal security agency told AFP it was "impossible to corroborate (the IS claim) at this point".

The Israeli army said the assailants appeared to have acted independently, like many of the attackers in a wave of unrest that has rocked Israel and the occupied territories since October 2015.

"A preliminary army intelligence evaluation found no evidence of them belonging to any group, rather they appear to have been a typical popular terror squad," an army spokeswoman said.

Hamas and the PFLP identified the three assailants as Bara Ata, 18, Osama Ata, 19, and Adel Ankush, 18, all from the village of Deir Abu Mashal near the West Bank city of Ramallah.

The Shin Bet said they had been implicated in previous "popular terror activity".

The PFLP said Bara and Osama Ata had recently been released from several months in Israeli prison.

A family member of one of the three flatly rejected any connection to IS, angrily telling AFP the jihadist group's claim was a "lie" that didn't deserve mention.

The army sealed off the assailants' home village while troops went house to house, arresting two youths before leaving after a number of hours.

- UN envoy 'appalled' -

Israel had eased restrictions on the entry of Palestinians to Jerusalem and Israel from the West Bank for Ramadan.

Following the attack, Prime Minister Benjamin Netanyahu decided to cancel permission for Palestinians to visit family members in Jerusalem and Israel, police said.

Netanyahu was also considering sealing off the Damascus Gate area to the public.

On Saturday, police cracked down on West Bank Palestinians without permits in Jerusalem, locating and sending home some 350.

Major General Yoav Mordechai -- head of COGAT, the Israeli defence ministry agency responsible for civilian affairs in the Palestinian territories -- said the 250,000 family visit permits were cancelled in response to "encouragement to terrorism" by Palestinian president Mahmud Abbas's Fatah movement.

In a Facebook post in Arabic, Mordechai charged that Fatah had congratulated the attackers.

A statement by Fatah carried on the official Palestinian news agency Wafa condemned the "killing" of the three Palestinians, without mentioning the circumstances leading up to their deaths.

Netanyahu meanwhile demanded that the Palestinian Authority, as well as the rest of the world, condemn the attack.