At least 29 Israeli troops were injured in battles across Gaza Strip in the last 24 hours, the army said Thursday.

The casualties come just over a day after at least nine soldiers were killed in an attack by Palestinian resistance group Hamas, marking the deadliest day for IDF in besieged Palestinian territory since the invasion began.

The soldiers were killed in an urban ambush, the military said Wednesday, a sign of the stiff resistance Hamas still poses despite more than two months of devastating bombardment.

The ambush in a dense neighborhood came after repeated recent claims by the Israeli military that it had broken Hamas' command structure in northern Gaza, encircled remaining pockets of fighters, killed thousands of militants and detained hundreds more.

The tenacious fighting underscores how far Israel appears to be from its aim of destroying Hamas – even after the military unleashed one of the 21st century's most destructive onslaughts.

Israel's air and ground assault has killed more than 18,600 Palestinians, according to Gaza's health officials. Gaza City and surrounding towns have been pounded to ruins.

Nearly 1.9 million people have been driven from their homes.

The resulting humanitarian crisis has sparked international outrage. The United States has repeatedly called on Israel to take greater measures to spare civilians, even as it has blocked international calls for a cease-fire and rushed military aid to its close ally.