The head of the UN, Antonio Guterres, urges Israel to stop its operation in the West Bank, saying it is "fuelling an already explosive situation"
Israel began what it called a "counter-terrorism operation" in four areas of the occupied West Bank on Wednesday, with at least nine people killed
The raids are believed to be the first time since the second intifada - a major Palestinian uprising from 2000 to 2005 - that several Palestinian cities have been targeted simultaneously
On the second day of raids, Israel's military says it killed five "terrorists" who had hidden in a mosque
At least nine Palestinians have been killed by Israeli forces in the north of the occupied West Bank, Palestinian health officials say.
The actual figure could be higher, with Palestinian officials earlier saying that at least 11 people had been killed since the Israeli operation began at midnight local time.
Violence has increased in the West Bank since the war in Gaza began, triggered by Hamas's deadly attack on southern Israel on 7 October.
The UN said last Wednesday, overall, more than 600 Palestinians had been killed in the West Bank, including East Jerusalem. This includes 589 killed by Israeli forces, 11 by Israeli settlers, and seven where the perpetrators remain unknown.
Israel has built settlements housing some hundreds of thousands of Jewish people since it occupied the West Bank and East Jerusalem - land the Palestinians want as part of a future state - in the 1967 Middle East war.
The settlements are considered illegal under international law, although Israel disputes this.
Meanwhile in central Gaza, the medical charity Médecins Sans Frontières (MSF) has opened a field hospital in Deir Al Balah to treat hundreds of patients who were evacuated from the city's main hospital at the weekend.
Around 650 patients were forced to leave the al-Aqsa hospital in Deir Al Balah on Sunday following an evacuation order by Israeli forces, and an explosion around 250 meters from the hospital, MSF says.
MSF says the first patients are arriving but it warns that there's a severe lack of supplies and resources.
"Field hospitals are not a solution, but a last resort in response to Israel’s dismantling of the health care system," MSF says in a statement.
According to the World Health Organization (WHO), 20 out of 36 hospitals in Gaza are now non-functional, and temporary structures like field hospitals lack the capacity for advanced surgical care, and many other lifesaving essentials to treat patients in critical condition or with long-term medical conditions.
Yolande Knell
Middle East correspondent, in Jerusalem
Local journalists are saying they haven't seen anything of this scope and scale in the West Bank since the days of the second Palestinian intifada, or uprising, two decades ago.
Israeli media says hundreds of Israeli forces active in four different cities at least in the north of the West Bank.
There have been air strikes carried out. We're hearing of gun battles going on inside the urban refugee camps.
The Israeli military has only put out a short statement on how it's working with other security forces on a "counter terrorism operation".
Israel's Foreign Minister Israel Katz has put out a strongly worded statement saying the military has been acting since last night with full force - aiming to dismantle Iranian Islamist terrorist infrastructure.
He has said the threat must be addressed with the same determination of the threat from Gaza including possible Palestinian evacuations - something we haven't heard in an official capacity before.
He's not speaking on behalf on the military at this stage but clearly he wants that to be a message going out to the world.
We're getting some images now from the occupied West Bank, where the Israeli military says it's been carrying out an "operation" to combat terrorism.
An Israeli military bulldozer was pictured during a raid in the northern city in Tulkarm this morning:
Image source, Getty Images
Image source, Getty Images
Image source, Getty Images
Image source, ReutersIsrael's Foreign Minister Israel Katz says the Israeli military has been "operating with full force" since last night in the Jenin and Tulkarm refugee camps in the West Bank.
He says they are working "to dismantle Iranian-Islamic terror infrastructures established there".
He accuses Iran, which backs the armed groups Hamas and Palestinian Islamic Jihad, of seeking to open what he calls a "second front" against Israel in the West Bank.
"We must address this threat with the same determination used against terror infrastructures in Gaza, including temporary evacuation of Palestinian residents and any necessary measures.
"This is a war, and we must win it.”
Yolande Knell
Middle East correspondent, in Jerusalem
This appears to be a major Israeli operation with at least four Palestinian cities being targeted at the same time: Jenin, Tulkarm, Nablus and Tubas.
Palestinian reports say that the main roads into Jenin have been closed off with armed clashes in the city's refugee camp.
An Israeli air strike is said to have targeted a vehicle in a nearby village at dawn. Israeli forces are said to have entered a hospital in Jenin and blocked off two in Tulkarm.
Israeli military raids of Nablus are reportedly focused on two refugee camps there.
In al-Far’a refugee camp near Tubas, medics say ambulances are struggling to reach the wounded after an Israeli drone strike.
The Israeli military has given few details but has said that it was acting with the domestic security service to combat terrorism.
Aoife Walsh
Live editor
At least 11 Palestinians have been killed by Israeli forces in the north of the occupied West Bank, Palestinian health officials say.
There are also reports of Israeli military activity involving the use of tanks and bulldozers in the Palestinian cities of Ramallah, Qalqilya and Tulkarm in the West Bank.
Six people died in a drone strike and armed clashes near Jenin and five were reportedly killed in an air strike in al-Far’a refugee camp in the Jordan valley.
Israeli security forces say it is carrying out "a counterterrorism operation" in the north of the occupied West Bank.
It is believed to be the first time since the second intifada - a major Palestinian uprising from 2000 to 2005 - that several Palestinian cities have been targeted simultaneously in this way.
Stay with us for live updates.