A Turkish court on Friday freed a 16-year-old high school pupil arrested for "insulting" President Recep Tayyip Erdogan, amid accusations his detention was the latest sign of a lurch to authoritarianism under the strongman leader.

The boy, Mehmet Emin Altunses, was released following a complaint by his lawyer, but he still faces trial in the future, the official Anatolia news agency reported.

Turkey and Armenia should not expect to resolve a long-running dispute over the mass killing of Armenians in World War I on the 100th anniversary of the tragedy in 2015, a top adviser to the prime minister said.

Armenia and its diaspora want Turkey to recognize the mass killings of Armenians in the final years of the Ottoman Empire from 1915 as genocide, something Turkey has so far vehemently resisted.

Iraq and Turkey on Thursday pledged to join forces to fight Islamic State insurgents who are holding swathes of Iraq and Syria.

"ISIS threatens not only Iraq's and Turkey's security but the entire region," Iraqi Prime Minister Haidar al-Abadi told a joint news conference with his Turkish counterpart, Ahmet Davutoglu, using an alternative name for IS jihadists.

A Turkish teenager who survived a severe head injury inflicted by the police in last year's anti-government protests was sentenced to more than three months in jail, local media reported on Thursday. 

A 16-year-old high school student has been arrested in central Turkey for "insulting" President Recep Tayyip Erdogan by accusing him and his ruling party of corruption, sparking angry criticism on Thursday from the opposition.

The boy, identified by his initials M.E.A., was believed to be a member of a leftist organization, the Hurriyet newspaper reported.

Turkey's long-running bid to join the European Union has suffered a tough blow amid an acrimonious dispute over a crackdown on opposition media, but analysts say there still remains hope its candidacy is not yet dead in the water.

Recent police raids on media outlets affiliated with tough-talking President Recep Tayyip Erdogan's top foe, the US-based cleric Fethullah Gulen, sparked an angry exchange with Brussels, which said the arrests undermined media freedom.

Turkish Prime Minister Ahmet Davutoglu on Sunday accused the European Union of starting a "dirty campaign" against Turkey by criticizing the arrests of opponents of President Recep Tayyip Erdogan.

Turkish President Recep Tayyip Erdogan on Saturday praised as "clean and lawful" the legal process against his opponents that has been sharply criticised by the EU and includes an arrest warrant for his arch-foe Fethullah Gulen.

"I have been watching this process closely as president of this country. Everything is lawful and in line with procedure ... a really diligent and clean process is going on at the moment," Erdogan said in a televised speech in Istanbul.

A Turkish court on Friday acquitted Turkish dissident sociologist Pinar Selek, who has taken refuge in France, over a 1998 explosion that killed seven people, the official Anatolia news agency reported.

The ruling -- delivered by a high criminal court in Istanbul -- came at a hearing on Selek's retrial after a life sentence for her alleged involvement in the deadly explosion was overturned this year, according to Anatolia.

Turkish prosecutors on Friday requested an Istanbul court to issue an arrest warrant for the US-based Muslim cleric Fethullah Gulen who has emerged as President Recep Tayyip Erdogan's number one foe.

The request by prosecutors said Gulen, who has lived in exile since 1999, led a "criminal" group acting against the "rules and laws in media, economy and bureaucracy," the state Anatolia news agency reported.