New York: US President Barack Obama and Iraqi Prime Minister Haider Al Abadi will strategise about the upcoming offensive to take back the northern city of Mosul when they meet on the sidelines of the UN General Assembly.

Increasingly, and not without irony, Iraq has become the bright spot in Obama’s campaign against Daesh, though profound challenges remain.

In neighbouring Syria, the chaotic civil war continues to plague efforts to defeat Daesh extremists, but in Iraq, cooperation with Al Abadi’s forces has helped the US-led coalition wrest back half the territory that Daesh once held, according to the US.

Yet a key city remains under Daesh control: Mosul, Iraq’s second-largest city and the extremist group’s stronghold in the country. An intensely difficult urban fight to oust Daesh from Mosul is expected to ramp up in the next two to three months, following recent victories in reclaiming other Iraqi cities including Fallujah and Ramadi.

Some one million people could be displaced by the battle in Mosul, US and UN officials say. Washington considers the Iraqi government’s handling of the displacement to be a major test case for reconciliation in Iraq, given the blend of sectarian groups with an interest in the northern city’s future.

“We’ve always believed that progress on the battlefield needs to be accompanied by continued political progress among Iraq’s different communities,” Ben Rhodes, Obama’s deputy national security adviser, said ahead of the meeting scheduled for Monday.

He said that Obama and Al Abadi planned to discuss preparation for an “effective and sustainable campaign to liberate Mosul”.

The session comes at a critical time for Obama, who has just a few months left in office to make progress against Daesh before passing on the conflict to his successor. The Obama administration considers Al Abadi to be a major improvement over the sectarian approach of his predecessor, Nouri Al Maliki, though Al Abadi has faced serious domestic political challenges in recent months.

Obama’s meeting with the Iraqi leader marks the start of a hectic week of diplomacy as he makes his final appearance as president at the annual UN gathering.

Obama also planned to meet Chinese Premier Li Keqiang on Monday and socialise with US diplomats who work at the UN. He was also to raise money in private for Senate Democrats, a day after holding another fundraiser for Hillary Clinton. The Democratic presidential nominee was holding her own programme of meetings with foreign leaders attending the UN summit as she works to portray herself as more presidential than Republican Donald Trump.

On Tuesday, Obama will give his farewell speech to the General Assembly, meet Nigerian President Muhammadu Buhari, and co-host a summit on the refugee crisis stemming largely from the Syria conflict. The US has told invited countries they must show up with significant commitments in hand to resettle and support more refugees.

Obama planned to take part on Wednesday in a US-Africa forum and meet Colombian President Juan Manuel Santos before returning to Washington.