As the earliest stages of a massive assault on Gaza City take shape, Israel is calling up tens of thousands of reservists to take part in the impending military operation.

The defence ministry approved the plan despite fears it will worsen the already catastrophic humanitarian crisis in the enclave.

Defence Minister Israel Katz's move, confirmed by a spokesperson, piled pressure on Hamas as mediators pushing for a ceasefire in the nearly two-year war in Gaza awaited an…