GAZA   -  Israel has agreed to a series of pauses in fighting in Gaza in September to allow young children in the enclave to be vaccinated for polio, according to United Nations and Israeli officials.  Rik Peeperkorn, the World Health Organization’s representative for the West Bank and Gaza, told a press briefing from a video link Thursday that the pause would start September 1 and will be split into three 3-day phases.

“We have a preliminary commitment for area-specific humanitarian pauses during the campaign,” he said, adding that the pauses will roll out first in “central Gaza for three days, followed by south Gaza and then followed by north Gaza.”

An Israeli official confirmed to CNN that polio vaccinations will begin in Gaza on September 1. Each phase of the vaccination campaign is expected to take around seven hours, and during those hours, the vaccines will be able enter the area on “pause” and be distributed.

COGAT, the Israeli agency responsible for approving aid into Gaza, did not immediately respond to CNN’s request for more information about how the distribution would be structured.  Basem Naim, a member of Hamas’ political bureau, said the militant group welcomed the push for a pause in Gaza to implement the vaccination drive. “We are ready to cooperate with international organizations to secure this campaign,” he added. At least a dozen Palestinians have been martyred after Israeli forces launched widespread raids in the occupied West Bank.

The Israel Defense Forces (IDF) said on Wednesday it was beginning a “counter-terrorism operation”. On Thursday, it said 12 people had been killed in the cities of Jenin and Tulkarm.

The Palestinian health ministry reported a higher death toll, saying 16 people had been killed since Wednesday morning.

The United Nations has called on Israel to de-escalate the ongoing raids, and the Palestinian mission to the global body has condemned the attacks.  UN Secretary General Antonio Guterres has called on Israel to immediately halt its operation, saying it was “fuelling an already explosive situation”.

He urged Israeli forces to “exercise maximum restraint and use lethal force only when it is strictly unavoidable”. The IDF said five were killed after “exchanges of fire” in Tulkarm with militants who had “hidden inside a mosque”. It said seven people had died in Jenin. Mohammed Jaber, who is also known as Abu Shujaa, was among those killed, according to the Israeli military. He was reportedly the local leader of the Tulkarem Brigade, which is backed by the Palestinian Islamic Jihad militant group.

The IDF said Jaber was linked to a number of attacks on Israelis, and was planning more.

The Tulkarm Brigade said in a statement on Telegram that its fighters ambushed an Israeli infantry unit “in response to the assassination of our commander”, without naming him.

The IDF said it had apprehended 10 wanted suspects, and recovered explosives and weapons during raids in Tulkarm and Jenin.

The Palestinian Mission to the UN condemned the raids in a letter on Thursday, saying the Israeli military had “invaded homes, deliberately targeted civilians, destroyed vital infrastructure and even besieged the four main hospitals in the area”.

In Jenin, ambulances were being stopped and checked by military jeeps parked around the government hospital as security forces continued their operation in the city’s refugee camp.

The camp is a base for armed groups, as well as a home to unarmed civilians, and has been the scene of many fierce gun battles in the past.

Israeli forces have blocked access to the camp and Palestinian phone networks are down.

It is the second day of what Israeli media say could be a days-long operation in the West Bank.

It is one of the largest such actions in the West Bank since the days of the second Palestinian intifada, or uprising, two decades ago.