Three people were wounded, including one policeman, in an explosion Friday at a police checkpoint near the Syrian border in the southern Turkish town of Suruc, local officials said.

The cause of the blast was not immediately clear but Turkish media said emergency service vehicles rushed to the scene.

Turkey's former president Abdullah Gul on Thursday vigorously defended his conduct after coming under heavy fire in pro-government media for staying on in an official presidential residence half a year after leaving office.

Gul, who handed over the presidency to his long time ally Recep Tayyip Erdogan after August elections, is still living in the luxurious Huber Kosku (Huber Mansion) above the shores of the Bosphorus in the Istanbul suburb of Tarabya.

Security forces in Turkey detained 13 foreigners and a Turkish citizen attempting to cross into Syria to join the Islamic State (IS) jihadist group, the armed forces said on Wednesday.

The army said that the group was detained on January 9 as they sought to cross the border into Syria from a village in the southeastern province of Gaziantep. 

Foreign fighters are flocking to Syria at an "unprecedented" rate, with more than 20,000 volunteers from around the world joining the Islamic State or other extremist groups, U.S. intelligence officials said Tuesday.

The foreign fighters have traveled to Syria from more than 90 countries, including at least 3,400 from Western states and more than 150 Americans, according to the latest estimate from the National Counter-Terrorism Center (NCTC).

The outgoing head of Turkey's top court launched a final broadside against President Recep Tayyip Erdogan on Tuesday, warning that the judiciary was being turned into an "instrument of revenge" by politicians.

Constitutional Court chairman Hasim Kilic, who announced he was retiring a month early, said the government's "extraordinary interest" in the court's affairs was undermining judicial independence.  

Journalist Firas Hatoum and his colleague Rony Rmaity were temporarily detained by Turkish authorities on Tuesday for illegally entering the embattled Syrian town of Kobane, reported al-Akhbar daily.

It said that the LBCI television journalist was seeking to film a report for the channel from Kobane, but the advances made by the Islamic State group in the area forced him to alter his plans.

Turkish President Recep Tayyip Erdogan on Tuesday expressed fury at the surprise resignation of his influential spy chief and said his arch enemy, the U.S.-based preacher Fethullah Gulen, had wreaked more havoc on the country than Kurdish militants.

The head of Turkey's National Intelligence Organisation (MIT) Hakan Fidan resigned at the weekend to stand for parliament, with Erdogan then stunning commentators by saying he did not approve of the move.

Turkey and Russia on Sunday tentatively agreed on the route for their planned Turkish Stream gas pipeline which Moscow hopes will replace its now scrapped South Stream project.

Turkish Energy Minister Taner Yildiz and Gazprom chief executive Alexei Miiller surveyed the route over the Black Sea during a four-hour ride by helicopter from Istanbul.

Turkish President Recep Tayyip Erdogan said on Sunday he was unhappy with the decision by powerful intelligence chief Hakan Fidan to resign from his post and stand for parliament in June elections.

"I do not view Hakan Fidan's candidacy positively," Erdogan said in televised comments at Istanbul airport before heading on a visit to Latin America.

Thousands of members of Turkey's Alevi religious minority on Sunday held a mass rally in central Istanbul, demanding greater rights and the preservation of the country's secular system.

The Alevis, who belong to an offshoot of Shia Islam, are Turkey's biggest religious minority, believed to make up at least 10 percent of the population.