04 July, 2017
Kemal Kilicdaroglu, the leader of Turkey's pro-secular Republican People's Party (CHP), signed the appeal to the European Court of Human Rights on Tuesday before setting off on the next leg of his long walk to Istanbul.
The march is expected to end Friday at the Istanbul prison where he is being held.
Accusing the CHP of sympathizing with Kurdish militants and the alleged mastermind of the July 15 failed coup, he said the road taken by Kilicdaroglu was "the way to Qandil and Pennsylvania".
The opposition leader was Saturday walking through the Akyazi district of Sakarya province on day 17 of the march, heading towards the town of Sakarya from where he will have a walk of around 150 kilometers (90 miles) to Istanbul.
Kilicdaroglu launched his march in Ankara on June 15 after Enis Berberoglu was jailed for 25 years for espionage, becoming the first lawmaker from the party imprisoned in a government crackdown in the wake of the attempted coup.
"The path which you are taking is the one of Qandil, the one of Pennsylvania", he said, referring to the northern Iraqi mountains where the PKK is based and the US state where Erdogan's ally-turned-foe Fethullah Gulen lives.
The referendum, which Erdogan won with 51.4 percent of the vote, allows Turkey to switch its governing system from a parliamentary one to a presidential system, abolishing the office of the prime minister while boosting the president's powers.
The CHP contested the outcome citing irregularities, including the electoral board's decision to count as valid unstamped ballots despite the law.