The call reflects worries that Europe 's gas imports , much of which pass through Ukraine 's pipelines , could be threatened .
Europe /location/location/contains Ukraine
DT NN VBZ NNS IN NNP POS NN NNS , RB IN WDT NN IN NNP POS NNS , MD VB VBN .
Europe
LOCATION
Ukraine
LOCATION
/location/location/contains