In the occupied West Bank city of Jenin, residents are struggling to return to normality after the longest – and deadliest – Israeli military operation in the area for 20 years. On Sunday – the start of the working week – traffic choked the city centre for the first time in nearly two weeks after roads were repaired; street vendors sold peaches and the first of the season’s pomegranates as the city slowly came back to life.

But in some places, sewage still flowed through streets dug up by military bulldozers. Many burnt-out buildings showed signs of fierce fighting, the upper floors now peppered with bullet holes and broken windows. Water and electricity infrastructure was severely damaged, and it is not clear when these services will be restored.

The destruction across large parts of the town was unprecedented, said Abu Mahmoud, 61, who opened his children’s clothing shop for the first time in 10 days, after it was clear the Israelis had left.

“Even in the second intifada it wasn’t like this, they didn’t destroy the roads and streets and go house to house,” he said, referring to the bloody Palestinian uprising of the 2000s, during which Jenin was at the centre of the violence.

“The young men of the town are fighting the occupation, yes, because they can’t find work and they don’t see a future. But we did not start this. The Israelis forced this on us.”

In the early hours of 28 August, hundreds of Israeli troops, police and intelligence operatives descended on Jenin, Tulkarem, Nablus, Tubas and Qalqilya in the north of the West Bank as part of what the Israel Defense Forces (IDF) called Operation Summer Camps, employing what the UN called “lethal war-like tactics”.

The Israeli military has been targeting Palestinian militant groups in these areas since spring 2022, after a string of attacks on Israelis. Violence in the West Bank has also been fuelled by the actions of far-right settlers and their backers in the ruling coalition, led by the prime minister, Benjamin Netanyahu.

Until now, raids have mainly focused on urban refugee camps, including one in Jenin, built to house Palestinians expelled from their homes after the creation of Israel in 1948. Today the camps resemble densely built, poorly serviced slums, where poverty, crime and militancy are rife.

The already deteriorating situation in the West Bank has vastly worsened since the war in Gaza broke out: Operation Summer Camps was launched almost immediately after the IDF decided to upgrade the territory’s status to a “secondary front”.

A failed suicide bombing in Tel Aviv last month – the first since the second intifada – appears to have spurred the new military policy. The offensive was the biggest in the West Bank since the war began in October, and by some measures the largest in the territory since the second intifada drew to a close in 2005.

During the eight-day operation, the IDF said it killed 14 fighters – among them regional leaders of Hamas and Islamic Jihad – and arrested another 30. It also said it confiscated “large quantities of weapons” and dismantled “terror infrastructure sites”. One soldier was reported killed.

According to the Palestinian health ministry in Ramallah, 36 people were killed during the West Bank raids, including 21 in Jenin, without differentiating between militants and civilian deaths. Eight children and two elderly people were among the dead, the ministry said. Nidal Abu Saleh, the mayor of Jenin, said the infrastructure damage was estimated at $13m.

The new generation of fighters based in the camps is only loosely affiliated with the traditional Palestinian factions: instead, many the Guardian spoke to said they would fight under the banner of whichever group was able to arm and fund them.

Abu Mahmoud said: “Imagine you are a young person here: there is no work, no alternative except the resistance. Seven people I know have lost at least two kids.

“Israel doesn’t distinguish between the factions. In some senses neither do we. We are all Jenin together.”

The city and camp residents described horrific conditions during the raid, during which about 20,000 people were trapped in their homes without water or electricity and little food; ambulances evacuating the wounded were stopped by soldiers looking for militants.

Khuld Amer, a 39-year-old teacher, and her husband, a civil servant, live with their four children in a five-storey modern building a street away from the camp. Since 2022, soldiers have regularly used their roof as a sniping position; in 2023, troops forced all 50 people living in the building into one room for 12 hours without food or water, and since then most families now flee to relatives’ homes when they realise the IDF are coming. If they stay, the soldiers force them out anyway.

Amer and her family came back to their flat this time to find smashed laptops, a blocked toilet and broken balcony door. “There must have been a woman soldier here or more than one, because it’s clear they were using my shampoo and cosmetics,” she said. “There was blond hair in my hairbrush. It’s a little thing, a drop in the sea compared to what the people in Gaza are going through. But it still shouldn’t be happening.”

She is desperate to sell the flat and move to her in-laws’ village for the children’s sake, but unsurprisingly, there are no buyers. “The apartment was 400,000 shekels (£81,000) and we have seven years left on the mortgage. But we’ll be lucky if we sell it for half that,” she said.

It is hoped a ceasefire in Gaza would do much to calm tensions in the West Bank, but despite the renewed efforts of international mediators, a truce and hostage release deal does not appear to be on the horizon.

Instead, Jenin’s residents are bracing for worse to come. With sewage on his shoes as he surveyed the damage to his home in the baking midday heat, 18-year-old Qasem al-Hajj said he did not think Operation Summer Camps had achieved its goals.

“Generation after generation, the resistance will endure and get stronger,” he said.