By Nidal al-Mughrabi and Fadi Shana DOHA/GAZA (Reuters) – Israeli tanks and aircraft hit targets in southern and central Gaza on Sunday and there were fierce gun battles in some areas as the war reached 100 days since the Oct. 7 attack led by gunmen from the Islamist Hamas movement. Communications and internet services were down for the third day running, complicating the work of emergency and ambulance crews trying to help people in areas hit by fighting. The clashes were concentrated in the southern city of Khan Younis, where Hamas said its fighters hit an Israeli tank, as well as in Al-Bure…