millions of people flee the country. now, refugees themselves are also becoming a weapon that s being used against poland. cnn s kyung lah explains. reporter: poland is already waging a war with russia. it s just not the kind you imagine. nearly 2.5 million ukrainian refugees have crossed into the safety of poland as war ravages their country. packing poland s arenas, lining up for government benefits, and sending their children to public schools. these innocent faces are part of vladimir putin s war of mass migration. it s a kind of a callousness that we just don t understand here. reporter: retired arm yu lieutenant colonel alexander vindman is known as a crucial witness in former-president trump s first impeachment proceedings but he was also a child refugee from ukraine whose family moved to the u.s. in 1979. refugees have been a weapon for a long time. russia is used refugees as a