Bulgaria has voiced anger at Turkey's open support for a party for the ethnic Turkish minority.
Bulgaria has voiced anger at Turkey's open support for a party for the ethnic Turkish minority, which is running in the general elections for the first time on March 26.
"Some of the pressures there that we see (and) hear seriously upsets us. On one hand you talk about democracy but on the other, you put serious pressure on Turks. This will not work," Erdogan said during a speech in Ankara, without offering examples.
Relations between the two NATO allies have been severely strained during the election campaign as Turkish officials including Ankara's envoy to Sofia back the Dost party.
Bulgaria is home to a 700,000-strong ethnic Turkish minority, a legacy of the Ottoman empire.
Meanwhile, over 200,000 ethnic Turks with Bulgarian passports who left Bulgaria during the communist era live in Turkey. One third of this community regularly takes part in Bulgaria's elections.
"I hope that the Bulgarian elections pass peacefully, and results come in a fair and transparent manner," Erdogan said.
He added Turkey did not have "an eye" on anyone else's territory or sovereignty.
Last week Bulgarian President Rumen Radev accused neighbouring Turkey of "interference" in the country, adding Sofia would not accept it.
The spat with Sofia comes with Ankara's ties with the European Union under heavy strain after Turkish ministers were banned from campaigning on the continent for a 'yes' vote in the April 16 referendum on expanding Erdogan's powers.
As the row showed no signs of abating, Erdogan warned on Wednesday that Europeans risked being unsafe on the world's streets if Europe continued to "behave like this".
The EU responded by summoning the Turkish envoy to the bloc on Thursday to explain Erdogan's remarks.