Angela Merkel and top EU officials travel to Turkey on Saturday for a high-stakes visit which will see them walk a diplomatic tightrope between keeping Ankara sweet over a crucial migrant deal and taking a stand on European values.

European Council head Donald Tusk, European Commission Vice President Frans Timmermans and the German chancellor will visit a refugee camp at 1100 GMT in Gaziantep on the Turkish-Syrian border.

Russia on Friday denounced Turkey's position on the conflict between Azerbaijan and Armenia over the Nagorny Karabakh region after a Russian-mediated ceasefire ended the worst clashes in decades in the breakaway enclave.

"Statements made by Turkish leaders are totally unacceptable for one simple reason -- they are calling not for peace but for war," Russian Foreign Minister Sergei Lavrov told a news conference in the Armenian capital of Yerevan.

Three Turkish soldiers were killed and others wounded Friday by a roadside bomb in the Kurdish majority southeast of the country, medical and military sources told AFP.

The explosion was caused by a home-made bomb on the side of a road between Tunceli and Elazig in a region caught up in bloody reprisals between the army and rebels from the outlawed Kurdistan Workers' Party (PKK).

Four Turkish academics went on trial Friday for "terrorist propaganda" in the latest of a series of court cases highlighting growing restrictions on free speech under President Recep Tayyip Erdogan.

Riot police stood guard outside the courthouse in central Istanbul, where two journalists accused of divulging state secrets attended the third hearing of their espionage trial, before staying on to watch the scholars' case.

Turkey's highest appeals court on Thursday overturned scores of convictions over an alleged coup plot against the government of then prime minister Recep Tayyip Erdogan.

The court threw out an earlier verdict by an Istanbul court which saw many top military officers convicted, saying the original trial had failed to uncover proof of the alleged plot in 2003, media reports said.

Turkey has frozen the assets of former Yemeni President Ali Abdullah Saleh and his son, in line with U.N. Security Council sanctions against the ousted strongman, the government said Thursday.

All assets belonging to Saleh and his son Ahmed Ali Abdullah Saleh in Turkish banks and other financial institutions "are frozen until February 26, 2017," read an announcement in the government's Official Gazette.

A Syrian national who was arrested on suspicion of belonging to the Islamic State group has committed suicide in a Turkish prison, local media reported on Wednesday.

Nedim Bellus, 35, was detained by Turkish police in an operation last week on suspicion of being an IS member and imprisoned in Iskendurun, a town in Hatay province near the Syrian border, the private Dogan news agency reported.

The EU hailed progress in curbing migrant flows from Turkey Wednesday following last month's landmark deal, vowing to propose visa free travel for Turks next month if Ankara meets its obligations.

Brussels made the announcement after Turkish Prime Minister Ahmet Davutoglu warned that Ankara could tear up the agreement if the European Union did not implement the visa pledge.

The Turkish army killed 32 suspected fighters from the Islamic State group in northern Iraq on Tuesday following an attack on one of its tanks, Turkish media reported.

Turkish troops destroyed a building used by IS, killing 10 jihadists and then killed another 22 fighters who tried to flee the scene, the Anatolia news agency said.

President Recep Tayyip Erdogan warned the European Union Tuesday it needs Turkey more than Ankara needs the bloc, as tensions grew over promises for visa liberalization in a crucial deal on stemming the flow of migrants to Europe.

Turkish Prime Minister Ahmet Davutoglu had earlier bluntly told the EU that Ankara would no longer abide by the March migrant accord if Brussels fails to implement the pledge to grant Turks visa-free travel by June.