Israeli forces sharply stepped up an offensive against Palestinian militants in Gaza on Thursday, fighting running battles with gunmen and killing 11 people in the worst violence since the cross-border operation began. Gunmen also killed a soldier in northern Gaza, where clashes raged, Al Jazeera television said. The army had no comment. Prime Minister Ehud Olmert ordered tanks to push deeper into Gaza overnight after militants from the ruling Hamas movement fired rockets into a major Israeli city for the first time. The incursion — nearly a year since Israel quit Gaza after 38 years of occupation — expands an offensive that began last week with the main goal of bringing home a captured soldier. Full Story