Palestinian health officials said at least 18 people had been killed in Jabalia and eight elsewhere in Gaza in Israeli strikes.\
The Israeli military said in a statement its troops had dismantled infrastructure and tunnel shafts and killed alleged fighters in the Jabalia area.
Troops had helped thousands of civilians to evacuate safely through organised routes, it said, contradicting reports from the U.N. aid agency. Israel was in contact with the international community and Gaza's healthcare system to ensure hospital emergency services were operating, it said.
Last week, the United States told Israel it must take steps in the next month to improve the humanitarian situation in Gaza or face potential restrictions on U.S. military aid.
Israel has intensified its campaigns both in Gaza and Lebanon after the killing of Hamas leader Yahya Sinwar last week had raised hopes of an opening for ceasefire talks to end more than a year of conflict.
It has vowed to eradicate Hamas, the group who formerly controlled Gaza and whose attack on Israel last year triggered the war, but in doing so has laid waste to much of the territory and killed tens of thousands of people. More than 1.9 million people have been left destitute and desperate for food.