Israeli airstrikes have killed at least 31 people in the Gaza Strip in a day, Reuters quotes Palestinian medics as saying, with nearly half of the deaths in northern areas where the army has waged a month-long campaign.

Palestinians said the new aerial and ground offensives and forced evacuations were “ethnic cleansing” aimed at emptying two northern Gaza towns and a refugee camp of their population in order to create buffer zones. Israel denies this, insisting it is fighting Hamas gunmen 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 camps and the focus of the army’s new offensive.

The rest were killed in separate Israeli airstrikes in Gaza City and in southern areas, including one in Khan Younis, which health officials said had killed eight people, including four children.