Members of the Iraqi federal police patrol Mosul during an operation to retake the city from ISIS.
Irbil, Iraq CNN  — 

The Iraqi army says it has recaptured a bridge across the Tigris River in west Mosul, where fierce battles are ongoing to oust ISIS from its last bastion in Iraq.

While all five bridges linking the government-held eastern Mosul to the western part have been destroyed, the takeover of the fourth bridge will allow Iraqi forces to lay a ramp over the broken part and open a supply route from east.

“The Rapid Response Forces of the Iraqi Federal Police completely liberated al-Jawsaq neighborhood and control the fourth bridge… Iraqi flags are now raised on buildings, and heavy casualties were inflicted on ISIS,” Lt. Gen. Abdel Amir Rasheed Yarallah of the Joint Operations Command said Monday.

Government forces retook the eastern bank from ISIS a month ago, completing a key phase in an offensive on Mosul that began on October.

The battle to take over west Mosul, where about 750,000 people are believed to be living, has proved to be challenging. The narrow, densely-populated streets there makes the impact of heavy weaponry deadly and indiscriminate, and access to aid difficult.

The United Nations food agency said accounts by residents in west Mosul were very alarming.

Displaced Iraqis flee the city of Mosul during an operation to retake the city from ISIS.

“Through telephone interviews, many distressed families said that food was unaffordable, while others said they could not access food at all,” the WFP’s Iraq chief Sally Haydock said. “Due to increased fighting, people are afraid to leave their homes, making it even more difficult to search for essential food items.”

According to government figures, almost 4,000 people fled west Mosul since the launch of the military operation in western Mosul on February 19.

As a result of the two and a half years of ISIS rule in Mosul, many of those newly-displaced have found themselves in a legal limbo without proper identification documents. Some lost their documents as they fled ISIS, while others were holding birth and marriage documents issued by ISIS that are not recognized by the Iraqi government.

A Peshmerga soldier checks passports at a checkpoint near Mosul in November

According to officials with the UN High Commissioner for Refugees, nearly half of the displaced they interviewed were in need of legal help to obtain legal documents.

Civil identity cards are essential for traveling and passing through checkpoints, as well as getting access to public services, such as food assistance, health care and housing assistance.