A "health disaster of widespread proportions" is unfolding in Gaza, as hospitals struggle to cope with Israeli air strikes, the UN has warned.

Chris Gunness from the United Nations Relief and Works Agency told the BBC medical services are "on the verge of collapse".

Health officials in Gaza say 30 Palestinians died early on Sunday as Israeli air strikes continued.

Israeli PM Benjamin Netanyahu has said the operation will continue until it restores security to Israelis, with Israeli media reporting fresh militant rocket attacks into the country.