Israel toughened its campaign against Gaza Sunday, warning Palestinians in the north to flee after marines mounted a ground attack, and diplomatic efforts to halt the bloodshed intensified. As world powers prepared to meet over the spiralling bloodshed, the Palestinian death toll from a punishing Israeli air campaign hit 165, following the bloodiest day yet in which 56 people were killed. Despite increasing calls for a ceasefire, Israeli Prime Minister Benjamin Netanyahu said there was no end in sight, with the military warning residents of northern Gaza to flee by 0900 GMT. "We are hitting Hamas with growing force," Netanyahu told the weekly cabinet meeting.