Iraqi Federal Police celebrate in the Old City of Mosul, Iraq, on July 8, 2017.

:: ISIS has captured most of a village south of Mosul despite losing control of its stronghold in the city, an Iraqi army officer and residents said, deploying guerrilla-style tactics as its self-proclaimed caliphate crumbles.

Prime Minister Haider al-Abadi declared victory over ISIS in Mosul on Monday, marking the biggest defeat for the hardline Sunni group since its lightning sweep through northern Iraq three years ago.

But the militants, armed with machine guns and mortars, have now seized more than 75 percent of Imam Gharbi, a village on the western bank of the Tigris river some 70 km (44 miles) south of Mosul, and reinforcements are expected, the Iraqi army officer said.

ISIS launched its attack on Imam Gharbi last week, in the kind of strike it is expected to deploy now as US-backed Iraqi forces regain control over cities the group captured during its shock 2014 offensive.

Mosul resident Hind Mahmoud said by telephone that she had heard exchanges of gunfire in the Old City and seen an Iraqi army helicopter firing on ISIS militants on Tuesday.

The top US general in Iraq said that security forces would still need to clear ISIS hideouts in Mosul, where as many as a couple of hundred fighters could remain, and would rest before fighting against the group in Tal Afar.