United Nations, March 4: Some 15,000 children have fled Iraq's Mosul city over the previous week where fighting between the security forces and the Islamic State (IS) terror group is intensifying, the UN Children's Fund (Unicef) announced."Unicef is responding to the immediate needs at the Hamam Al Alil camp, 20 km from Mosul, where aid is provided to children upon their arrival," the agency's Regional Emergency Advisor Bastien Vigneau said on Friday.He noted that the children were very scared of the sound of the bombs, which was one of the main reasons their parents had decided to flee. They fled with very little luggage and in most cases with a bare minimum of clothes, Xinhua news agency reported. The main priorities, other than the first emergency response, included health, to ensure that children were immunised, primarily against measles and polio, said Vigneau.Matthew Sarmash, spokesperson for the Office of the UN High Commissioner for Refugees (Unhcr), said that a significant increase in displacement had been noticed in recent days and the Hamam Al Alil camp was close to reach its maximum capacity.At the moment, 150,000 places were occupied. He said construction is under way to accommodate up to 250,000 people there.Vigneau said that more than 100,000 children have been displaced from Mosul since the military operations against the IS began in October 2016.The troops' advance toward Mosul came after Iraqi Prime Minister Haider al-Abadi announced on February 19 the start of an offensive to drive the extremist militants out of west Mosul, locally known as the right bank of Tigris River which bisects the city.In January, al-Abadi declared the liberation of the east of Mosul, after more than 100 days of fighting against the IS militants.However, west Mosul, with its narrow streets and a heavy population of between 750,000 and 800,000, appears to be a bigger challenge to the Iraqi forces, according to UN estimates.Mosul, 400 km north of the Iraqi capital of Baghdad, has been under IS control since June 2014.