Presidential candidate Selahattin Demirtaş said a fair vote in next month's election was impossible under the state of emergency.
The party's former co-leader has been in jail for a year and a half on security charges and faces up to 142 years in prison if convicted.
In his first interview with international media since being named as the candidate by his pro-Kurdish Peoples Democratic Party (HDP) on Friday, Demirtaş told Reuters "opposition parties will face huge obstacles campaigning for votes."
"Demonstrations are banned, talking is banned, criticising the government is banned, even defending peace is considered terror propaganda," he said. "Hundreds of opposition journalists are arrested, dozens of TV and radio channels are closed.
"It is impossible for there to be fair elections in such an environment," Demirtaş said in a hand-written response to questions submitted by Reuters to his lawyers.
"There is no legal obstacle to my candidacy because I am not convicted," he said, adding it would be a "scandal and a crime" if the courts blocked him by convicting him.
"The AKP government is losing its support rapidly. The economy is also being dragged into a crisis. The government plans to control the state before hitting rock-bottom," he said.
However, (HDP) had left the door open to a possible alliance between HDP and the Turkish President Recep Tayyip Erdoğan's AKP party. "I cannot say anything about what will be in the future. The upcoming process will primarily focus on the removal of blocked political channels," HDP co-chair Pervin Buldan had told Sputnik Radio.
The part recently had declared that the HDP open for a possible alliance with Turkey's Hezbollah — unrelated to its Lebanese namesake — affiliated Hüda-Par party.
Communist Party of Turkey (TKP) declared that the party participate the general elections with independent candidates in various provinces under the slogan "This Social Order Must Change". Regarding the presidential elections to be held on the same day with general elections, the TKP calls for the people to turn their back on not only to the candidates, but also to this election and the political regime it represents.
