Bulgaria has returned dozens of migrants detained aboard a freight train from Greece back to its southern neighbor.
The migrants returned on May 29 included 56 Afghans. It was the first time Bulgaria had deported migrants to Greece.
A separate group of some 40 Syrians and Iraqis detained on May 28 were expected to be deported at a later date.
The migrants were all detained on May 28 in what was the largest number of people caught trying to enter the Eastern European country since the start of the migrant crisis.
"We have sent a strong message to traffickers who are exploiting these unfortunates," Bulgarian Interior Minister Rumyana Bachvarova said after the Afghan migrants were returned to Greece.
Greece's border with Macedonia, just to the west, is now effectively closed to migrants, sparking fears in Bulgaria that they may instead try to transit its territory on their way north.
Bulgaria shares a 500-kilometer border with Greece.