Israeli forces have severed northern Gaza from the rest of the besieged territory and pounded it with intense airstrikes overnight. That sets the stage for an expected push into the dense confines of Gaza City and an even bloodier phase of the month-old war. Palestinians held a mass funeral on Monday for dozens of people killed a day earlier in strikes in the south, where Israel has urged people to seek refuge. Troops are expected to enter the city soon, and militants who have prepared for years are expected to fight street by street using a vast network of tunnels.