GENEVA, Oct 21 (Reuters) - More social mixing indoors after the lifting of restrictions just as winter sets in is driving a rise in COVID-19 infections in many countries across Europe, the World Health Organization"s emergency director Mike Ryan said on Thursday. "Most of those restrictions are now not in place anymore in many countries. And we"re seeing that coincide with the winter period in which people are moving inside as the cold snaps appear," Ryan told a news briefing. "The question remains as to whether or not we will have the same experience as last year with health systems coming once again under pressure." Russia has recorded its highest daily hospital death toll from the disease in a very long time, while the week-on-week rise in COVID-19 cases in Britain was less than in parts of eastern Europe, he said.