Turkey’s main opposition leader, Kemal Kilicdaroglu, currently on a 425-km walk to Istanbul on a "Justice March", said on July 4 that the Republican People’s Party (CHP) is to appeal to the European Court of Human Rights (ECHR) over the Supreme Election Board’s (YSK's) decision to accept unstamped ballot papers during the April 16 constitutional referendum, news agencies reported.

Turkish President Recep Tayyip Erdogan officially narrowly won the right to create a powerful executive presidency in the referendum, but its outcome was immediately challenged by the CHP and some academic experts.

“YSK’s decision made the referendum illegitimate. Now, we have prepared our petition. We are applying to the European Court of Human Rights,” Kilicdaroglu told reporters.

He added: "Turkey has rapidly turned into a (one-)party state. Pretty much all state institutions have become branches of a political party. This is causing profound harm to our democratic, parliamentary system."

As the march has advanced, Erdogan has stepped up his attacks on it, saying the CHP was no longer acting as a political opposition, according to Reuters, which reported him as saying in a speech to officials at the weekend: "We can see that they have reached the point of acting together with terror groups and those powers which provoke them against our country."

CHP’s earlier attempts to get the referendum results annulled have all failed within the Turkish judicial system.

Party leader Kilicdaroglu’s protest march from the capital Ankara to Istanbul has entered its 20^th day. He hopes to arrive in Istanbul on June 9. Some senior figures from the main opposition party have said that the CHP is planning a massive rally in Istanbul on July 9.

On June 3, Kilicdaroglu warned that there could be provocation against the crowd that is followinng behind him as his march nears Istanbul.

“We are hearing that some provocations could take place as we are getting closer to Istanbul. I want all participants to respond to any kind of provocations with applause,” Hurriyet Daily News quoted him as saying.

A spokesman for the ruling AKP accused the CHP of “leading the country into chaos” with the march.

“The CHP is concealing its efforts to create chaos by abusing the concept of justice. I wish Kilicdaroglu would be sincere in his demand for justice. If they were really sincere, then they would support our efforts to bring the July coup plotters [who failed with their attempted putsch in the summer last year] to account for their actions and they would stand with the victims,” AKP spokesperson Mahir Unal said, again according to Hurriyet Daily News.

Meanwhile, the government is planning events between July 11 and 16 across Turkey to mark the first anniversary of the bloody coup attempt.

“Some 81 provinces in Turkey will host commemoration events, but the majority of the activities will take place in Istanbul and Ankara,” spokesperson for the president İbrahim Kalin reportedly said on July 3.

Erdogan will attend some of those events in the capital and Ankara, according to Kalin.