Israeli forces stepped up bombardment of the Gaza Strip killing at least 23 people, Palestinian medics said, with over half the deaths in northern areas where the army has waged a month-long campaign it says is to prevent Hamas from regrouping, Reuters reports.

Palestinians said the new aerial and ground offensives and forced evacuations were “ethnic cleansing” aimed at emptying two north Gaza towns and a camp of their populations to create buffer zones. Israel denies this, saying it is fighting Hamas who launch attacks from there.

Medics said at least 13 Palestinians were killed in separate attacks on houses in Beit Lahiya town and Jabalia, the largest of the enclave’s eight historic refugee camps and the focus of the army’s new military offensive. The rest were killed in separate Israeli air strikes in Gaza City and the southern areas.

Israel has not commented on its military actions in northern Gaza.