Some 677,000 have fled Ukraine to neighbouring countries since Russia launched an invasion of the country last week, according to the United Nations’ top official for refugees. Around half of of those people have arrived in Poland, UN High Commissioner for Refugees Filippo Grandi said. Around 90,000 were in Hungary and tens of thousands in other neighbouring countries such as Moldova, Slovakia and Romania, he added. Within 24 hours, the total number of Ukrainian refugees as estimated by the UN refugee agency (UNHCR) had increased by 150,000. Many of the people who have fled so far are thought …