The United Nations has voiced grave concern over escalating violence in the West Bank, demanding that Israeli security forces “immediately” stop supporting settler attacks on Palestinians in the occupied territory.

The statement from the UN’s human rights office was issued hours after two Palestinian men were killed by Israeli settlers in a northern village south of Nablus, in the latest violent attack involving settlers in the increasingly tense West Bank.

Salah Bani Jaber, the mayor of Aqraba, a town near the northern city of Nablus, saw Monday’s settler attack. He said about 50 settlers, many of them armed, attacked members of his community and fired at Palestinian youths, killing two of them and wounding others.

“There were Israeli soldiers at the scene who stood idly by watching the settlers,” he said.

The Palestine Red Crescent Society said soldiers blocked its ambulances from reaching the area and tending to the wounded. The Israeli military said it was looking into the incident.