Top diplomatic and military officials from the international coalition fighting the "Islamic State of Iraq and the Levant" (ISIL) met for a second day Thursday (July 21st) to prepare the assault on Mosul, the group's stronghold in Iraq, AFP reported.

Defence and foreign ministers from more than 40 countries gathered in Washington, D.C., as their local allies made advances in Syria.

Mosul will be the campaign's centre of gravity in the weeks and months to come.

"Let us remember, Mosul is where [ISIL leader] Abu Bakr al-Baghdadi declared his phony caliphate in June of 2014," said Brett McGurk, the US special presidential envoy to the Global Coalition to Counter ISIL.

"And if we get this campaign right on the ground, in all its aspects, it is where we can begin to seal his fate," he said.

On the first day of the talks, the defence ministers met separately to talk battlefield tactics while the foreign ministers pledged $2 billion in reconstruction funds.

Thursday's meeting brought them together to discuss how to ensure that any victory in Mosul is quickly followed by a political settlement and the return of refugees.