Bulgaria will not stop a wave of refugees from Turkey if Ankara opens its borders, Bulgarian Prime Minister Boyko Borissov said Friday amid the ongoing anti-terror operation in northern Syria.

"If 50,000-100,000 migrants come to the fence (along Bulgaria's border with Turkey), neither I nor Karakachanov (Deputy Prime Minister and Defence Minister Krassimir Karakachanov) will order the army or the police to open fire. They will bring the fence down and will cross," Borissov said.

The prime minister noted that now the pressure on the Bulgarian border "is zero," which is why the agreement between Turkey and EU should be observed.

"As of this moment, our relations with Turkey are perfect, and this is one more factor of the quiet situation on our border," Borissov said, adding that Bulgaria's relations with Turkey are "good-neighbourly."

Borissov's remarks come a day after President Recep Tayyip Erdoğan called on the EU to "pull itself together" and warned that if the bloc labelled the anti-terror operation in northern Syria an occupation he would "open the gates and send 3.6 million refugees" to Europe.

Turkey launched Operation Peace Spring, the third in a series of cross-border anti-terror operations in northern Syria targeting terrorists affiliated with Daesh and the PKK's Syrian offshoot the People's Protection Units (YPG), on Oct. 9 at 4 p.m.

The operation, conducted in line with the country's right to self-defense borne out of international law and U.N. Security Council resolutions, aims to establish a terror-free safe zone for Syrians return in the area east of the Euphrates River controlled by the U.S.-backed Syrian Democratic Forces (SDF), which is dominated by YPG terrorists.

The PKK — listed as a terrorist organization by Turkey, the U.S. and the European Union — has waged a terror campaign against Turkey for more than 30 years, resulting in the deaths of nearly 40,000 people, including women, children and infants.

Turkey has long decried the threat from terrorists east of the Euphrates in northern Syria, pledging military action to prevent the formation of a "terrorist corridor" there.

Since 2016, Turkey's Euphrates Shield and Olive Branch operations in northwestern Syria have liberated the region from YPG/PKK and Daesh terrorists, making it possible for nearly 400,000 Syrians who fled the violence to return home.