BAGHDAD - The UN mission in Iraq said on Monday that bombs planted by the Islamic State group are hindering the return of displaced families to the country's western city of Ramadi, nearly two months since Iraqi forces, aided by U.S.-led coalition airstrikes and Sunni fighters took it back from the extremists.

UN development official, Lise Grande, said that such unexploded bombs have killed eight people in the past two weeks. The eight died either while surveying their homes or attempting to disable devices inside the city, she said.

"People who have been displaced want to return home as quickly as possible," Grande said in a statement. "Making sure they can do so safely is everyone's responsibility. Booby-traps and IEDs have to be cleared first."

Ramadi, the provincial capital of Anbar, fell to the Islamic State group in May, a major setback for U.S.-allied Iraqi forces at time. It was liberated in December. At the height of the group's strength, IS controlled more than a third of Iraqi territory before a U.S.-led campaign of airstrikes began in August 2014.

Unexploded bombs and damaged infrastructure continue to be a key challenge to the return of normalcy in areas freed from IS.

Last month, Anbar's Governor Suhaib al-Rawi told reporters that efforts to clear Ramadi of explosives are slowed by a lack of funding. Iraq's economic crisis has left the province in debt and entirely reliant on international aid donations to rebuild. An initial assessment of destruction in Ramadi carried out by the UN in January said more than 4,500 buildings have been damaged or destroyed during the battle to reclaim the city.

In Iraq, more than 3 million people have been forced to flee their homes since January 2014, according to the United Nations. It estimates that an additional 3 million people are living under IS control in Iraq.

In contrast, about 500,000 civilians have returned to their homes following the Iraqi military campaigns to bring areas back under government control.