A Liberian judge has sentenced 13 men to life in prison for "mercenary activity" in neighbouring Ivory Coast, state radio has reported.
The men, all Liberian nationals, were convicted for their role in attacks on villages in western Ivory Coast in 2011 and 2012. The seven UN peacekeepers from Niger were killed while on patrol in the region of Tai near the border with Liberia.
One of their lawyers, Tiawan Gongloe, has said that the jury's verdict was not supported by law, and the legal team planned to appeal the conviction and the sentence, handed down on Tuesday.
Sporadic raids from Liberia into Ivory Coast have continued. Last week's verdict was the first under Liberia's mercenary law.
Ivory Coast was rocked by months of post-election violence after former President Laurent Gbagbo refused to step down despite losing the November 2010 presidential runoff to Alassane Ouattara.
After the conflict, many pro-Gbagbo fighters along with Liberian mercenaries who supported Gbagbo fled into neighbouring Liberia, where they are believed to have launched cross-border attacks.
An attack in Ivory Coast in June 2012 killed seven UN peacekeepers, sparking international pressure on Liberia to curb mercenary activity.
Gbagbo was ousted from power in April 2011 and incarcerated in The Hague that November. He faces charges at the International Criminal Court with orchestrating violence carried out by his supporters after Ivory Coast's 2010 elections. He denies wrongdoing.
Ouattara is now the Ivory Coast president.
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 UN 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.