Somali pirates on Tuesday freed a German-American journalist and writer, Michael Scott Moore, two and a half years after he was kidnapped in the war-torn Horn of Africa nation, officials said.

A Somali pirate source, who asked not to be named, said a ransom was paid for his release, without giving more details.

The German government has confirmed that two Christian aid workers and their son who were kidnapped five years ago in Yemen are dead, citing "reliable intelligence", a relative said Tuesday.

The couple, identified only as technician Johannes H. and his wife Sabine, then both aged 35, and their three young children were abducted in June 2009 in northern Yemen.

German police have arrested a Turkish man suspected of having fought for the Islamic State jihadist group in Syria, public prosecutors said Monday.

The 40-year-old, who lives in Berlin and is a Turkish citizen, was detained by a special police unit in the German capital Friday, a spokesman for the city public prosecutor's office said.

Relatives of German victims of downed Malaysia Airlines flight MH17 plan to sue Ukraine and its president for criminal negligence for not closing the country's airspace, a lawyer said Sunday.

Elmar Giemulla, an attorney and professor of aviation law who is representing three German families, said he would file suit soon before the European Court of Human Rights in Strasbourg. 

Prosecutors brought formal charges on Friday against three Germans accused of sending money and camera equipment to help the jihadist group Islamic State make propaganda videos.

The accused were identified only as Karolina M., 25, who has been in pre-trial detention since March, as well as Jennifer Vincenza M. and Ahmed-Sadiq M., both 22, who have not been detained.

Muslims across Germany held a day of prayer and rallies Friday to condemn both Islamic extremism and a backlash against their faith that has seen arson attacks on mosques.

Some 2,000 mosques joined the event "Muslims against hatred and injustice" organized by Germany's four main Islamic groups, together with government ministers, lawmakers, Christian and Jewish leaders and city mayors.

Qatar's emir said in Germany on Wednesday that his wealthy Gulf state does not back Islamic "terrorist organizations", and Chancellor Angela Merkel said she had no reason to doubt him.

The leaders spoke in Berlin where the emir was visiting, some three weeks after a German minister angered Doha by linking it to financing of the jihadist militant group Islamic State (IS).

The French, German and Russian foreign ministers on Monday held closed-door talks in Paris over the Ukraine crisis, a German foreign ministry official said.

There were however no details of the discussions between France's Laurent Fabius, Germany's Frank-Walter Steinmeier and Sergei Lavrov of Russia after a giant international conference on fighting Islamic State militants in Iraq.

An alleged German jihadist went on trial Monday accused of fighting in Syria for the Islamic State group, amid calls for tougher action to prevent attacks in Europe by militants.

In the first German criminal proceedings involving IS, Kreshnik Berisha, a 20-year-old born near the business capital Frankfurt to a family from Kosovo, has been charged with membership of a foreign terrorist organization.

German Chancellor Angela Merkel and Jewish leaders will speak Sunday at a Berlin rally against anti-Semitism after the latest Gaza conflict sparked an upsurge in hate speech against Jews.

Under the banner "Stand Up: Jew Hatred - Never Again!" political and religious leaders and thousands of people are expected at the rally from 1300 GMT at the iconic Brandenburg Gate.