Turkey's interior minister and his delegation on Friday paid an official visit to the Bulgarian capital Sofia, reported Yenisafak News.

During the visit, Süleyman Soylu met with his Bulgarian counterpart Mladen Marinov and Prime Minister Boyko Borisov. Both meetings were closed to the media.

"The minister's visit will reinforce historic ties between the governments and peoples of the two strategic and friendly allies, and also help explore new areas of bilateral cooperation and collaboration, particularly in the area of economic, trade and commercial relations," according to sources of the ministry who spoke on condition of anonymity.

Borisov told Soylu about his great friendship with Turkish President Recep Tayyip Erdogan and the excellent cooperation between the two countries, according to Turkish officials.

Muhterem Ince, deputy interior minister of Turkey; Hasan Ulusoy, Turkey's ambassador in Sofia; Bulgarian chief prosecutor Sotir Tzatzarov and many other high-level officials attended the meetings.

The meetings focused on security cooperation to fight organized crime, drug trafficking, irregular migration and terrorism, as well as eliminating the financing and funds of terror groups such as the Fetullah Terrorist Organization (FETÖ), PYD/PKK, DAESH and DHKP-C, the sources added.

The minister lauded Bulgaria's stance against FETÖ.

"One of the important extraditions of FETÖ [members] first came from Bulgaria. The same determination is still present in Bulgaria today," Soylu told reporters at Turkey's Sofia Embassy, during his visit.

He added that Bulgaria was ready to fight along with Turkey.

He went on to say that both countries have a serious and result-oriented cooperation in the fight against organized crime and drug.

FETÖ and its U.S.-based leader, Fetullah Gulen, orchestrated the defeated coup of July 15, 2016, which left 251 people martyred and nearly 2,200 injured.

Ankara accuses FETÖ of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.