UN secretary-general Antonio Guterres has condemned Israel’s “excessive force” in an operation against a refugee camp in the West Bank.

He criticised Israel for preventing medical care and humanitarian workers reaching those in need after the attack on the Jenin refugee camp, which he said left more than 100 civilians injured, forced thousands to flee, damaged schools and hospitals and disrupted water and electricity networks.

Mr Guterres said: “I strongly condemn all acts of violence against civilians, including acts of terror.”

Calling on Israel “to abide by its obligations under international law”, he said the condemnation “applies to all use of excessive force, and obviously in this situation, there was an excessive force used by Israeli forces”.

“The use of air strikes is inconsistent with the conduct of law enforcement operations,” he said.

He reminded Israel that “as the occupying power, it has a responsibility to ensure that the civilian population is protected against all acts of violence”.

The secretary-general’s condemnation followed a statement by three UN independent human rights experts on Wednesday which said the Israeli airstrikes and ground actions “amount to egregious violations of international law and standards on the use of force and may constitute a war crime”.

The experts on human rights in the Palestinian territory, on the rights of the internally displaced, and on violence against women and girls, called for Israel to be held accountable for its illegal occupation and violent acts to perpetuate it.

Israel’s two-day offensive meant to crack down on Palestinian militants destroyed the Jenin camp’s narrow roads and alleyways, forced thousands of people to flee their homes and killed 12 Palestinians. One Israeli soldier also was killed.

The Israeli army claimed to have inflicted heavy damage on militant groups in the operation at the camp which ended Wednesday.

Ahead of the Israeli withdrawal, prime minister Benjamin Netanyahu vowed to carry out similar operations if needed.

An Israeli soldier was killed when a Palestinian opened fire near the West Bank settlement of Kedumim on Thursday. The army said the gunman opened fire after his vehicle was stopped for an inspection and was shot dead after a brief chase.

A spokesperson for the Palestinian militant group Hamas praised the shooting as a “heroic act” and a “natural response” to the Israeli raid on Jenin.

On Friday, Israeli forces killed two Palestinians in Nablus, the West Bank’s commercial capital.