By David Lawder WASHINGTON (Reuters) – The World Bank and International Monetary Fund said on Thursday they were working to keep their remaining employees in Ukraine safe amid a Russian invasion while the institutions’ leaders said the conflict was greatly raising economic risk in the region. “Most of our staff have already relocated outside Ukraine. Some staff remain in Ukraine for extenuating personal and family reasons,” World Bank President David Malpass said in an internal staff memo seen by Reuters. “We will continue to identify options for those who have decided to not leave the country…