Any so-called Islamic State (IS) fighters left in Mosul will die in the Iraqi city, a US envoy co-ordinating the offensive has said.
Brett McGurk, the senior US official in the counter-IS coalition, issued the warning after Iraqi forces cut off the last road out of the city, trapping IS fighters inside.
The jihadists have held Mosul, Iraq's second city, since 2014.
But Iraqi forces have managed to retake large areas in a months-long offensive.
They now control all of Mosul's eastern side, and the latest US-backed push against IS - which began on 5 March - has forced the extremists from key locations in the west, including the main local government headquarters and the famed Mosul museum.
Heavy fighting continued over the weekend, with Mr McGurk telling reporters in Baghdad on Sunday "just last night, the 9th Iraqi army division... cut off the last road out of Mosul".
He added "Any of the fighters who are left in Mosul, they're going to die there, because they're trapped.
"So we are very committed to not just defeating them in Mosul, but making sure these guys cannot escape."
Staff Major General Maan al-Saadi, of Iraq's elite Counter-Terrorism Service, said government forces now controlled "more than a third" of western Mosul.