Amid a row with Turkey over accusations of influencing its Turkish minority and dual citizens on their votes in Sunday's elections, Bulgaria banned a Turkish lawmaker from the ruling Justice and Development Party (AK Party) and two public officials from entering the country.

Ibrahim Tarancı, a clerk from Turkey's Edirne Governorate, was detained last week in the city of Shumen by Bulgaria's State Agency for National Security (DANS) on the grounds of "threating national security" and was deported to Turkey. An entry ban was imposed on Tarancı for five years, while a statement suggested that two others were added to the list of "undesirable aliens" for similar reasons without elaborating further.

Bulgarian media outlets suggested that these names were AK Party Istanbul lawmaker and former provincial chairman Aziz Babuşçu and Ulvi Ata, the religious affairs attaché of the Turkish embassy in Sofia.

Local newspapers suggested that Babuşçu attended the election rallies of Democrats for Responsibility, Freedom and Tolerance Party (DOST – which means "friend" in Turkish) headed by Bulgarian-Turkish politician Lütfi Mestan.

Babuşçu and Ata were in Turkey when their names were added to the list, thus the decision effectively bans their entry into Bulgaria. The interim government of Bulgaria further imposed entry bans on two other Turkish nationals on Friday, without disclosing their identities.

The incident comes as Bulgarian nationalists blocked three main crossing points with Turkey on Friday to prevent thousands of Turks with Bulgarian passports coming to vote for the elections on Sunday.

Bulgaria is home to a 700,000-strong Muslim minority, most of them ethnic Turks, while at least 200,000 ethnic Turks with Bulgarian passports live in Turkey. The two groups make up more than 10 percent of the population.

Traditionally they have voted for the centrist Movement for Rights and Freedoms (DPS - HÖH) led by Ahmed Dogan – the third party in the 2014 elections, nearly receiving 15 percent of the votes – but the party has become increasingly critical of the Turkish government. Most of the party members are of Turkish origin.

Last year a group headed by Mestan split off from the DPS and formed DOST as he was ousted from DPS leadership after openly backing Turkey in the spat with Russia in the jet downing crisis of Nov. 2015.

Turkish officials, including Turkey's ambassador to Bulgaria, have also openly voiced their support for the DOST party.

Last week, Bulgaria's caretaker government summoned Turkey's envoy to Sofia and also recalled its ambassador to Turkey for consultations.

Bulgarian Prime Minister Ognyan Gerdzhikov said this was to "prevent any attempts by Turkey to influence an election."

Sofia has complained about Turkish meddling, and in the latest exchange on March 23 Turkish President Recep Tayyip Erdoğan accused Bulgaria of putting "serious pressure" on Turks ahead of the vote.

Bulgarian President Rumen Radev said "Bulgaria neither gives nor accepts lessons in democracy, especially from countries that do not respect the rule of law."

Bulgaria will take to the polls for a parliamentary election on Sunday and the election is expected to be a close race between the Socialists, seen closer to Russia, and the center-right. A new grouping of nationalist "patriots" is tipped to come third.

Forming a government after the third election in four years in the European Union's poorest country will be tough, and experts say the resulting coalition may be short-lived.