Long road ahead for Mosul's residents, despite military victory over ISIS U.N. Refugee Agency says there is no end in sight to the humanitarian crisis.

 -- Iraqi Prime Minister Haider al-Abadi declared victory in Mosul Monday -- three years after ISIS took control of the city.

The nine-month campaign to retake what was once Iraq's second largest city is a major success for Iraqi Security Forces and the U.S.-led coalition supporting them. But Mosul's residents, nearly 700,000 who are still displaced, face a long road back to normalcy.

"While there may be an end to military conflict in Mosul, there is still no end in sight to the humanitarian crisis," the U.N. Refugee Agency (UNHCR) said Monday.

While residents have started returning to East Mosul -- which was liberated in January and sustained much less damage -- about 350,000 people are still living in emergency camps and unable to return to their homes, according to the U.N.'s Office for the Coordination of Humanitarian Affairs.

The U.N. predicts that thousands will remain displaced for months. Basic infrastructure such as water and electricity has been severely damaged. A senior U.N. official said just last week that it could cost $1 billion to restore those basic services.

“Many of the people who have fled have lost everything," said Lise Grande, the U.N.'s humanitarian coordinator for Iraq. "They need shelter, food, health care, water, sanitation and emergency kits. The levels of trauma we are seeing are some of the highest anywhere. What people have experienced is nearly unimaginable.”

While Mosul General Hospital's maternity ward reopened last Thursday after months of closure, other hospitals and schools will need to be entirely rebuilt or repaired, the U.N. said.

Like was done in Ramadi and Fallujah after those cities were liberated from ISIS, de-mining teams will also have to clear the streets of explosives.

"There's a lot to do in the weeks and months ahead," Grande said. "Of the 54 residential neighborhoods in western Mosul, 15 are heavily damaged and at least 23 are moderately damaged.”

The battle against ISIS continues

While Mosul has been liberated, the extremist group still holds pockets in other parts of the country, and residents remain under siege.

"The civilians who are trapped in the areas where fighting is likely to occur, including Tel Afar, Hawija and western Anbar, will be at extreme risk. We have to make sure we are ready to help them,” said Grande.

But now the fight against ISIS will mainly be focused on Raqqa, the group's de-facto capital in Syria and their last major stronghold.

Despite heavy casualties, there have been early successes. Syrian Democratic Forces, backed by the U.S.-led coalition, surrounded Raqqa's old city last week.

The U.S. military has said ISIS fighters are fleeing south along the Euphrates River -- with groups forming in Al Mayadin, Al Bukamal and other towns along the river.

"Make no mistake. This victory alone does not eliminate ISIS. And there is still a tough fight ahead," said Lt. Gen. Stephen Townsend, the commander of the U.S.-led coalition, in a video statement on Monday. "But the loss of one of its twin capitals, and the jewel of their so-called caliphate is a decisive blow to ISIS."