Using tunnels, mines, booby traps and snipers, Hamas fighters have inflicted record casualties on Israeli troops waging an offensive in the Gaza Strip, applying years of training in urban warfare with a new tactical acumen and suicidal resolve.

The Israelis say weapons and know-how supplied by Iran and its Lebanese ally Hezbollah make Hamas a more formidable foe.

Four days after Israel launched a withering ground assault on the Palestinian Islamist militants in their stronghold of Shejaia following intensive air strikes, the army still does not have complete control of the area. […]