Watch Greek police arrest illegal immigrants at Evros (video)
So far, police forces have pushed back 5,183 people at the borders
U.S says Greece has the right to apply border laws
A State Department official said the US was closely monitoring the situation on the Turkish-Greek borders
UPDATE: Read the new measures Greece takes to enhance border security after security meeting under PM Mitsotakis
"The present situation constitutes an active, serious, exceptional and asymmetric threat to the country's national security"
