A stronger migratory pressure can now be felt on the EU's external borders, the head of the common border protection agency has said.

The march of "more migrants" en route to Bulgaria from Greece or Turkey has been singled out as an issue, but the numbers are small compared to those in the Western Balkan countries last summer, he has added.

"To date we have sent some 112 employees to Bulgaria, but we need at least 100 more," Fabrice Leggeri has told Die Welt [DE] in an interview.

His words come as Bulgaria's Interior Minister Rumyana Bachvarova has said the country has demands some 300 FRONTEX staff to be deployed, but sees the number 200 as more realistic.

"Overall, we are going through a dispersion of the inflow. The migrants and smugglers are finding new routes," according to Leggeri.

He has also warned that the numbers of irregular migrants will increase substantially if the EU-Turkey deal falls through.

But he has also insisted there is "no evidence" so far of any deliberate moves by Turkey to send migrants into Europe.

"Throughout July we have counted around 1800 migrants arriving in Greece. To compare, in Fabruary and even in March as many were coming on a daily basis," he has said, praising Turkey's good cooperation with both FRONTEX and  Greek authorities.