By Bassam Masoud, Nidal al-Mughrabi and Dan Williams GAZA/DOHA/JERUSALEM (Reuters) -Israeli forces advanced into the southern Gaza Strip’s main city on Thursday, pounding areas near the enclave’s biggest functioning hospital, as Prime Minister Benjamin Netanyau vowed “many more months” of fighting until total victory is achieved. The heaviest battle of the year was under way in Khan Younis, sheltering hundreds of thousands of people who fled the north earlier in the war, now in its fourth month. Residents described heavy fighting and intense bombardment in the north and east of the city and, f…