* Prominent Al Jazeera journalist was detained on Saturday
* German government grilled on grounds for arrest
* Merkel criticized for hosting Sisi in early June (Recasts with Jazeera and German officials saying Mansour freed)
BERLIN, June 22 (Reuters) - A prominent Al Jazeera journalist was released in Germany on Monday, the television network and German authorities said, two days after he was detained at Berlin airport at Egypt's request.
Ahmed Mansour, one of Jazeera's best known journalists, was released without charge, the pan-Arab television channel's Berlin correspondent Eissa Taibi said. An official at the Berlin state prosecutor's office confirmed his release.
"I will definitely meet him today," Taibi said. "I do not have a lot of details about his release but the only thing I know is that he has been released and that his lawyer and Al Jazeera's lawyer were with him a short while ago."
A Cairo court sentenced Mansour to 15 years in prison in absentia last year on a charge of torturing a lawyer in 2011 in Tahrir Square, the focus of the uprising that toppled Hosni Mubarak. Mansour and Al Jazeera deny the charge.
Earlier on Monday the German government had played down the chances of him being extradited to Egypt, citing concerns about the Egyptian legal process, including group sentencings and doubts about due process.
"All these points will definitely ... be considered in the decision," Foreign Ministry spokesman Martin Schaefer told a government news conference.
Last year an Egyptian court jailed three Al Jazeera journalists on charges that included aiding a terrorist group. One of them, Australian Peter Greste, was released in February after 400 days in prison.
Mohamed Fahmy, a naturalized Canadian who has given up his Egyptian citizenship, and Egyptian Baher Mohamed were released on bail in February after spending more than a year in custody and are being retried.
Egypt accuses Al Jazeera of being a mouthpiece of the Muslim Brotherhood, the Qatar-backed Islamist movement that President Sisi removed from power in 2013 when he was army chief and denounces as a terrorist group.
Mansour's case puts Germany in an awkward position as it tries to strike a balance between business interests and human rights.
Chancellor Angela Merkel was criticized by opposition parties and rights groups for hosting President Abdel Fattah al-Sisi earlier this month. During that visit, German industrial group Siemens signed an 8 billion euro deal with Egypt to supply it with gas and wind power plants.
"I don't think one can say this loudly enough: Of course, nobody will be extradited from Germany who risks being sentenced to death abroad," Schaefer said.
Since Sisi took power in 2013 and won a presidential election the following year, courts in Egypt have issued scores of death sentences against Muslim Brotherhood members, including the group's leadership.
($1 = 0.8816 euros) (Reporting by Paul Carrel and Michelle Martin in Berlin, and Omar Fahmty and Yara Bayoumy in Cairo; Editing by Noah Barkin and Dominic Evans)