German police have arrested well known Al Jazeera Arabic journalist Ahmed Mansour at Berlin's Tegel Airport at the request of Egyptian authorities.

Fifty-two-year-old Mansour was detained at the airport on Saturday as he was boarding a flight to Doha, DPA reported. Police officials said the arrest warrant against him concerned several "unspecified" alleged offences.

Mansour was reporting on a recent visit of Egyptian President Abdel-Fattah al-Sisi to Germany at the time of his arrest. He is known for his loyalty to the presently-blacklisted Muslim Brotherhood group of ousted President Mohamed Morsi, according to Antara news agency.

"I informed ( the police) that the global police organisation has rejected Egypt's request and that I have this document from the Interpol to prove that I am not wanted in any charge," Mansour said in a phone call to Al Jazeera. Interpol rejected an Egyptian request for an international warrant against him in October last year.

"I also told them that all the cases that were filed against me in Egypt were fabricated. They, however, insisted on holding me in their detention centre for investigation. It is quite ludicrous that a country like Germany would enforce and support such a request made by a dictatorial regime like the one we have in Egypt," he said.

Mansour, who has dual Egyptian and British citizenship, was sentenced last year in absentia to 15 years in jail by an Egyptian court, DW reported. A Cairo court found him guilty of torturing a lawyer in Tahrir Sqaure in 2011.

"Ahmed Mansour is one of the Arab world's most respected journalists and must be released immediately," Al Jazeera acting director general Mostefa Souag said in a statement urging Germany to immediately release him. He will remain in German federal police custody until Monday, when he will face a German judge.

Mansour himself wrote about his arrest.

لازلت رهن الأعتقال فى مطار برلين فى انتظار تحويلى الى قاضى التحقيق والسؤال هو كيف تحولت الحكومة الألمانية... https://t.co/ui538Wbk5h

— Ahmed Mansour (@amansouraja) June 20, 2015

His Facebook page has flooded with messages calling for his immediate release.