Bulgaria's DOST party leader said on Tuesday that they will appeal to the Constitutional Court over obstacles expat voters faced in Sunday's general election

"We will appeal to the Constitutional Court to cancel the election results," Lutfi Mestan, who heads the Democrats for Responsibility, Freedom and Tolerance Party (DOST), told Anadolu Agency (AA).

Many Turkish-Bulgarian voters who live in Turkey were prevented from voting in the polls because of border protests.

Bulgaria also has a Turkish minority that makes up around 10 percent of the population, according to official census figures.

"In these elections, we were alone in the face of everyone, fighting not only political forces but the state and the government," Mestan said.

"I am sure that we would have been even more successful if the obstacles had not happened," he added.

DOST, which means "close friend" in Turkish, generally has ethnic Turks or Muslims among its members.

Former Prime Minister Boyko Borisov's center-right GERB party took the most votes in the early general election, winning 32.55 percent. DOST took 8.94 percent of the vote, failing to pass a threshold to gain parliamentary seats.

Mestan said the parliament "cannot represent the will of people" without DOST and accused nationalist United Patriots leaders of supporting the border protests.

"Bulgarian policy has been totally overtaken by racists but racist party leaders cannot be solely held responsible for these events," he said. "Other party leaders are also responsible for it."

Meanwhile, Nedim Dönmez, chairman of the Edirne Balkan Turks' Federation said his group would also launch legal action.

He told AA that in the 2016 general election, voters were able to use 140 ballot boxes in Turkey but this number was reduced to 35 on Sunday, a move the Turkish Foreign Ministry said was intended to hinder Turkish-Bulgarians from voting.

Dönmez said that two days before the election, Bulgarian officials decided that application forms would be completed in the rooms where the boxes were kept, causing further problems.

Turkish-Bulgarians who did not understand the Bulgarian language also had difficulty with the forms, he added.

According to Dönmez, there are around 200,000 people in Turkey eligible to vote.

On Sunday, around 30,000 were able to vote, compared to more than 90,000 in 2009, he said.

Dönmez said the legal challenge would first be lodged at Bulgarian courts but the case could go to the European Court of Human Rights if unsatisfied.

"We cannot tolerate restrictions on human rights," he said.

Sunday's election - the fifth time since May 2013 that Bulgarians have gone to the polls - took place amid tensions between Ankara and Sofia.

Disputes erupted over claims Turkey was favoring the DOST coalition and on Friday, right-wing activists staged a demonstration at the Kapitan Andreevo border to block expat Bulgarian voters living in Turkey from taking part.

The demonstrators, many brandishing anti-Turkey banners and Bulgarian flags, blocked traffic at the border, forcing passengers from Turkey to disembark from buses and walk across the frontier on foot.

Last week's protests also drew a response from senior Turkish Cabinet ministers.