* Case sparks tensions dating back to civil war
* Border raids into Ivory Coast are frequent
MONROVIA, June 17 (Reuters) - A Liberian court on Tuesday sentenced 13 people to life imprisonment for cross-border raids into Ivory Coast that killed seven U.N. peacekeepers in a controversial case.
The Liberian nationals were indicted for their alleged involvement in a series of attacks in neighbouring Ivory Coast between 2011-2012 in which they burned houses, murdered civilians and raped women. During raids on the Ivorian villages of Tai and Para in June 2012, seven peacekeepers from Niger were killed.
"I confirm and affirm the guilty verdict of the jurors. The verdict of the jurors met the law," said Judge Emery Paye on Tuesday, referring to an initial guilty judgment given last week and confirmed on Tuesday.
Dressed in bright orange jumpsuits, the men yelled after the verdict was handed down inside the heavily guarded courtroom.
Supporters of the convicted said the trial was a political witch hunt against the Krahn group - the ethnicity of former President Samuel Doe who was assassinated in 1990, sparking a 14-year civil war.
Current Liberian President and Nobel Peace Prize winner Ellen Johnson Sirleaf was imprisoned under Doe and is seen by some as holding a grudge against his supporters.
"The government have no proof," said Patience Sarpee, wife of Bobby Sarpee, who is accused of leading the attacks. Defense lawyer Tiawon Gongloe said he will appeal the decision at the Supreme Court.
Since 2011, Ivory Coast has complained of numerous border incursions into their territory by militia with links to Liberian rebel factions. An attack by gunmen at Ivory Coast's southwestern border with Liberia in May killed 13 people.
A U.N. report in May expressed concerned about Liberia's "weak capacity" to monitor its borders while Human Rights Watch has criticised Monrovia for failing to hold its nationals to account. (Reporting by Clair MacDougall and Alphonso Toweh; Writing by Emma Farge; Editing by Jonathan Oatis)