Kiev, April 11 : The UN Refugee Agency (UNHCR) said that more than 4.5 million people have fled Ukraine since Russia launched its ongoing war on February 24. As of Sunday, the UNHCR said there were 4,503,954 Ukrainian refugees, 62,291 more than the previous day, the BBC reported. According to the UN agency, this is the first time for Europe to witness such a large number of refugees since the Second World War. The UNHCR said that 90 per cent of those who have fled are women and children, as most men aged 18-60 are not allowed to leave Ukraine as they must stay and join the country's forces. Poland currently hosts the largest number of refugees from Ukraine, with 2,593,902 people crossing into the country since the beginning of the invasion, it added. Ninety-four per cent of the registered refugees in Poland are women and children. According to the UN's International Organization for Migration (IOM), around 210,000 non-Ukrainians have also fled the country. Figures published by the IOM on April 5 had revealed that an additional 7.1 million people, or more than a quarter of the overall population, have been displaced within the country. /IANS