The Israeli military kept up the pressure on northern Gaza on Wednesday, striking in a suburb of Gaza City, medics said, and told residents in a central part of the enclave to evacuate from an area where militants were firing rockets.

Gaza is a territory spanning 25 miles at its longest point, where the displaced are sheltering in tents on the beach.

More than 40 Palestinians have been killed in 15 Israeli air strikes across the Gaza Strip, according to the territory's Hamas-run Civil Defence service. The chief of Gaza's police force and his deputy were among 11 killed in an overnight attack on a tent camp for displaced families in the southern al-Mawasi "humanitarian zone", it said.