CAIRO (Reuters) -Israeli tanks pushed into southern and eastern areas of the Gazan city of Deir Al-Balah for the first time on Monday, an area where Israeli sources said the military believes some of the remaining hostages may be being held. Gaza medics said at least three Palestinians were killed and several were wounded in tank shelling that hit eight houses and three mosques in the area, and which came a day after the military ordered residents to leave, saying it planned to fight Hamas militants. The raid and bombardment pushed dozens of families who had remained to flee and head west towards the coastal area of Deir Al-Balah and nearby Khan Younis.