GAZA CITY, Gaza Strip — Tens of thousands of Gaza Palestinians marked the 13th anniversary of Palestinian President Yasser Arafat’s death Saturday for the first time since the Islamic Hamas group seized the territory a decade ago. In the wake of a brewing reconciliation between Hamas and the Fatah party Arafat founded, Fatah supporters flocked to al-Saraya Square in Gaza City from all over the coastal enclave to commemorate the event, waving their yellow flag, raising posters of Arafat and donning his trademark kaffiyeh headgear. Arafat died in 2004 at a hospital in France after two years of an Israeli siege on his West Bank headquarters.