Bulgarian border authorities have been attacking Afghan and other irregular migrants using police dogs and other violent methods to illegally push them back in the Turkish territory, an international rights group said Thursday.

Human Rights Watch (HRW) said that the migrants reported to have been beaten, robbed and stripped.

"Bulgarian authorities are brutally and summarily pushing back migrants and asylum-seekers across the land border with Turkey," said Michelle Randhawa, refugee and migrant rights officer at HRW.

"The European Union should ensure that Bulgaria immediately stops the illegal and dehumanizing pushbacks at its borders and allows asylum-seekers access to fair asylum procedures."

Bulgaria’s government didn’t immediately respond to HRW’s report. But officials have previously denied mistreating migrants.

HRW said it interviewed 15 Afghans between November and April who told the organization that they were "victims of 19 pushbacks by Bulgarian authorities from Bulgaria to Turkey."

In November, Bulgaria's Defense Ministry said it was deploying troops and army vehicles along its southern border with Turkey to help border police deal with a growing number of migrants trying to enter the country.

The Balkan country of 7 million is located on a major route for migrants from the Middle East and Afghanistan to Europe. Only a small number of them plan to stay in the EU's poorest member, using Bulgaria instead as a transit corridor on their way westward.

Last month, Turkish security forces found 84 semi-naked irregular migrants in a forest, who claimed to be stripped and pushed back by Bulgarian authorities. Turkish authorities also rescued hundreds of other irregular migrants pushed back by Bulgaria.

Turkey has been a key transit point for irregular migrants who want to cross to Europe to start new lives, especially those fleeing war and persecution.