Israel is conducting dangerous urban warfare but its ultimate goals remain uncertain

Evidence from the conflict zone suggests the IDF is seeking to encircle Gaza City as the military and Hamas report fierce initial battles

• Israel and Hamas at war - live updates

Israel's ground invasion of the northern Gaza Strip began on Friday evening, an urban warfare operation that is likely to be lengthy, fraught with danger for its military and Palestinian civilians and whose ultimate goals remain uncertain.

It began more than three weeks after Hamas's surprising and brutal cross-border attack of 7 October, in which 1,400 Israelis were killed, and comes amid what the monitoring group Airwars says is an aerial bombardment that far outpaces" the number of bombs dropped in the deadliest months" of the US-led war against Islamic State.