Turkey's governing party workers were campaigning in southeastern Sanliurfa province ahead of June 24 elections when the incident occurred.
Turkey's Deputy Prime Minister Bekir Bozdag on Friday blamed the PKK terrorist organisation for a deadly attack on governing Justice and Development (AK) Party members campaigning in southeastern Turkey, less than 10 days before national elections.
"It is very clear that the PKK terrorist organisation is behind them [attackers] and that they are pawns of the PKK terrorist group," Bozdag said at the AK Party headquarters in the central Yozgat province.
Since it resumed its armed campaign against Turkey in July 2015, the PKK has been responsible for the deaths of more than 1,200 Turkish security personnel and civilians.
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Perpetrators will face justice
Bozdag said that those responsible for the attack will soon face justice.
"I strongly believe that those who have carried out this attack and those who participated in this attack will be brought to account," he said.
"To destroy terrorism, to destroy terrorists, and to ensure our nation holds elections in a free environment, we will continue to make every effort, every endeavor," he added, referring to the June 24 presidential and parliamentary elections.
AK Party workers – including MP Ibrahim Halil Yildiz – were campaigning on Thursday when they were attacked by an armed group in Sanliurfa's Suruc district, leaving four people dead and eight injured.
Health Minister Ahmet Demircan said the police and an air ambulance were dispatched to the scene immediately.
Although Yildiz survived the attack with no injuries, his older brother Mehmet Ali Yildiz died after succumbing to his wounds in the hospital.
The Sanliurfa Governorship said in a statement that Yildiz, accompanied by a group of people, was visiting tradesmen in the centre of Suruc when a discussion turned into a fight.
Presidential Spokesman Ibrahim Kalin condemned the attack and said perpetrators behind it would be brought to justice.
Main opposition Republican People’s Party (CHP) leader Kemal Kilicdaroglu also reacted to the attack and said people should express their thoughts by voting in a democratic environment and not take park in clashes.
This April, the parliament passed a bill for early elections on June 24, cementing Turkey’s move to a presidential system.