Israeli aircraft struck Hamas sites in Gaza late on Saturday, the military said, in an escalation of hostilities after earlier cross-border gunfire seriously injured an Israeli soldier and wounded 41 Palestinians, including two critically.

The injuries came during a Gaza protest organised by the enclave's Islamist rulers Hamas and other factions in support of Jerusalem, where Palestinian clashes with Israeli police helped spark an 11-day Israel-Hamas conflict in May.

Hundreds of Palestinians gathered near the...