Israeli forces are using “lethal war-like tactics” in the occupied West Bank, according to the UN’s humanitarian agency.

The Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement on Wednesday that Israeli attacks have killed more than two dozen people over the past week or so, including children. The continuing raids, mostly concentrated on the Tulkarem and Jenin refugee camps, constitute Israel’s largest assault on the occupied territory since the second Intifada in the early 2000s.

The raids have seen significant violence and numerous arrests, while roads and other infrastructure have been destroyed by Israeli military bulldozers.

OCHA said it had mobilised organisations from the UN and beyond to assess the damage and humanitarian needs on the ground.

Visiting Tulkarem on Saturday, the teams confirmed the displacement of 120 people, including more than 40 children, whose homes were destroyed, the statement said.

“At the time of the assessment, 13,000 people in Nur Shams refugee camp experienced water cut-offs, attributed to damages caused to the water network, and sewage overflow was observed. The teams also noted that the population was traumatized and in need of psychosocial support,” OCHA said.

A similar assessment team was denied access to Jenin by the Israeli authorities on Wednesday.

“OCHA warns that access impediments are impacting the ability to provide meaningful humanitarian response. The movement of ambulances and medical teams has been impeded and delayed since the onset of the now-week-long operation. Humanitarian access must always be facilitated,” the statement said.

Israeli military’s latest assault in Jenin is in its eighth day, and the third day in Tulkarem, where Israeli forces are inflicting “widespread destruction”, according to the Wafa news agency.

Citing its correspondents on the ground, the agency said Israeli forces dropped bombs on the refugee camp, sparking fires in al-Shamaliya neighbourhood.

Israeli snipers were stationed on tall buildings, while spy drones flew and bulldozers damaged infrastructure, with “no street or alley left without destruction”, Wafa reported.

A siege of al-Israa and Thabet school was also continuing, it added.

Al Jazeera’s team on the ground also reported an ongoing Israeli raid in the Jalazone refugee camp, north of Ramallah. Sources said that dozens of Palestinians have been detained and questioned in local community centres.

At least 20 Palestinians have also been rounded up from Beit Surik. Most returned after they were interrogated.

Other raids were reported in Qalqilya, Nablus with a focus on Balata and Askar refugee camps, as well as al-Khader town south of Bethlehem and al-Azza refugee camp north of the city.

Israeli security forces have besieged Hebron for a fourth day running and more checkpoints and gates have been erected.