ERBIL, FIRAQ: The United Nations said on Thursday up to 200,000 more people could flee Mosul as Iraqi forces push into the last districts held by Islamic State militants.

Iraqi authorities and aid agencies are already struggling to cope with a surge in displacement since security forces opened a new front against the militants in Mosul earlier this month.

Backed by a US-led coalition, Iraqi forces have dislodged Islamic State from all but about 12 square km (5 square miles) of the city and are seeking to claim victory before the holy month of Ramadan in less than two weeks.

The militants, however, still control the Old City, where they are expected to make their last stand in the densely populated, narrow streets that are impassible for armored vehicles.

"As military operations intensify and move closer to Mosul’s Old City area, we expect that up to 200,000 more people will flee,” Lise Grande, the UN's Humanitarian Coordinator for Iraq said in a statement, describing the figures as "alarming".

“The numbers of people who are moving are now so large, it’s becoming more and more difficult to ensure civilians receive the assistance and protection they need."

Nearly 700,000 people have fled Mosul since the start of the campaign to retake the city last October, seeking refuge either with friends and relatives or in camps.

Human Rights Watch said on Thursday the Iraqi army and other local security forces had forced over 300 displaced families to return to districts of Mosul that are still at risk of attack by Islamic State.

“These families should not be forcibly returned to unsafe areas and areas that lack adequate water, food, electricity, or health facilities,” said Lama Fakih, deputy Middle East director at Human Rights Watch.