* Rwandan rebel leaders go on trial in Germany
* Trial a "precedent", but doubts linger over impact
(Adds Congo, FDLR and analyst reaction)
By Christian Ruettger
STUTTGART, Germany, May 4 (Reuters) - Two alleged Rwandan rebel leaders accused of ordering massacres and mass rape in the Democratic Republic of Congo went on trial in Germany on Wednesday.
Congo's government welcomed the trial and called on other nations sheltering rebel leaders to follow suit. But there are doubts over how much impact it will have on the ground in eastern Congo, where civilians have endured years of abuse.
The alleged head of the Hutu guerrilla group FDLR, Ignace Murwanashyaka, and the man accused of being his deputy, Straton Musoni, face 39 charges of war crimes and 26 of crimes against humanity committed in eastern Congo between 2008 and 2009.
Murwanashyaka is charged with commanding or endorsing atrocities such as the murder of more than 200 people, recruitment of child soldiers, arson, and looting while he was living in the southwest German city of Mannheim.
On the first day of the trial in Stuttgart, the defence demanded a dismissal of the proceedings, alleging bias on the part of state prosecutors -- who rejected such charges, a court spokesman told Reuters.
"This is a purely politically motivated trial," Ricarda Lang, Murwanashyaka's lawyer, told reporters. "An acquittal is the only possible outcome after conclusion of this trial."
The two men were arrested in Germany in 2009 in response to U.N. pressure for international action against the leadership of the Democratic Forces for the Liberation of Rwanda (FDLR).
Congo's information minister Lambert Mende said his government would provide information if asked. "We urge other countries giving refuge to FDLR leaders to follow Germany's example."
Founded in 2000, the FDLR is mainly made up of Hutus from Rwanda who fled to Congo after the 1994 genocide in which 800,000 ethnic Tutsis and moderate Hutus were killed.
Widely accused of being led by those who carried out the genocide, the FDLR played a major role in a 1998-2003 conflict in eastern Congo in which more than five million people died.
Murwanashyaka has been living in Germany for about 20 years, having arrived as a student. If found guilty, he and Musoni face life sentences which in Germany means at least 15 years in jail.
A U.N. envoy to Congo has said the arrest of the pair has demoralized FDLR forces. [ID:nN07235549]
But La Forge Fils Bazeye, a spokesman for the group in Congo, said others had replaced them.
Jason Stearns, author of Dancing in the Glory of Monsters, a book on Congo's conflicts, said the trial set an important legal precedent but it was unlikely to hurt the group's operational capacity on the ground and abuses would continue.
Rwandan-backed military operations over the last two years had done more to diminish their threat, he said.
Another FDLR leader, Callixte Mbarushimana, was arrested in France last November and transferred to the International Criminal Court in The Hague earlier this year.
According to the International Crisis Group, the FDLR had around 15,000 guerrillas in 2001 but its number has dwindled to about 3,500, according to U.N. experts. (Additional reporting by Reuters TV and Jonny Hogg in Kinshasa; Editing by David Lewis and Stephen Brown)