Iraqi forces began storming the ISIS-held Old City of Mosul on Sunday, in an assault they hope will be the last in the eight-month-old campaign to seize the militants' stronghold.
The historic district, and a tiny area to its north, are the only parts of the city still under control of the Islamists, Reuters reported.
"Iraqi forces early this morning breach into old Mosul, the final ISIS-held district in the city," the US envoy to the international coalition fighting ISIS, Brett McGurk, said on Twitter. "We are proud to stand with them."
