KHAN YOUNIS - Balanced on a steep slab of fissured concrete with rods of twisted metal poking out and the remnants of a dome slanted at a 45-degree angle behind him, a young muezzin in a baseball cap called Muslims to prayer from atop a bombarded mosque in Gaza.

The minaret, where the muezzin would usually stand, was still upright but appeared precarious, with a chunk missing from the balustrade at the top and the base resting on the jumbled ruin of the Al-Touba Mosque in Khan Younis in the southern Gaza Strip.

The mosque is one of many in Gaza that have been hit by Israeli strikes in its war against Hamas. Israel accuses the Islamist group of using mosques to conceal tunnel shafts, missile and rocket launch sites and other infrastructure.

Hamas denies this and accuses Israel of targeting places of worship including mosques and churches and making false accusations aimed at justifying civilian deaths.

Drone footage of three mosques in Khan Younis, filmed by Reuters on Wednesday, the sixth day of a truce that has since been extended by another day, showed the extent of the destruction of the religious buildings.

At Al-Touba, the dome that used to rise above the multi-storey mosque was completely gone. The only part of it still recognisable was its circular base, tilted sideways on the collapsed roof where the muezzin stood.

At Al-Ansari Mosque in a different part of town, a pile of dusty prayer mats could be seen in a chaotic pile inside a room filled with cement that had been crushed into what looked like pebbles. Tiles with Arabic writing and twisted metal railings were visible in a gap between a fallen ceiling and tilted walls.

Both mosques were located in densely built-up areas, with what looked like apartment blocks adjacent to them.

At a third mosque, Al-Ameen Mohammed, part of the yellow dome was still there, but with a huge gash at the top. The structure was also tilted at a steep angle as one side of the building below had collapsed.

Next to the mosque was an open expanse of sandy terrain where a tent camp for displaced people had sprung up. Beyond that were apartment blocks and the Mediterranean Sea.

The war was triggered by Hamas militants who rampaged through southern Israel on Oct. 7, killing 1,200 people including babies and children and taking 240 hostages of all ages, according to Israel.

Vowing to destroy Hamas in response, Israel launched a military assault on the densely populated Gaza Strip that has killed more than 15,000 people, 40% of them children, according to Palestinian health officials. A further 6,500 are missing, many feared still buried under rubble.

Two-thirds of Gazans have been displaced, most sheltering in Khan Younis and other southern areas after Israel ordered the complete evacuation of the northern half of the tiny coastal strip. U.N. Secretary-General Antonio Guterres has described the conditions in Gaza as an epic humanitarian catastrophe.

(Writing by Estelle Shirbon; Editing by Alison Williams)