Turkey has only granted a small number of all requests from Bulgarian authorities to take back migrants who crossed the common border over the last month, Bulgarian official estimates show.

Out of 314 requests, concerning a total of 437 people, Ankara has complied with 11, according to Interior Ministry data published on the institution's website.

The figure comes amid uncertainty over the future of a readmission agreement that Sofia and Ankara signed in May, but whose implementation was reportedly frozen by Turkey.

The document signed in May came within the framework of the EU-Turkey agreement on measures to curb the inflow of migrants into Europe.

In mid-June, however, Bulgarian authorities announced a hundred percent of requests filed by Bulgaria had been declined.

While Turkey's Embassy denied suspending the agreement, Bulgarian Interior Minister Rumyana Bachvarova later said the Turkish government was yet to come up with a statement.

Bachvarova then suggested Turkey might be waiting to complete ongoing talks with EU partners over the migrant deal, amid a deadlock between Brussels and Ankara over visa facilitation which was part of the agreement but but which the EU has tied to certain conditions.

Earlier this week Bulgaria urged Turkey to begin implementing the readmission agreement.