Central African Republic's livestock minister, a former rebel chief detained for war crimes and crimes against humanity, was on Friday freed from jail by gendarmes.
The Special Criminal Court in the capital Bangui, which tries rights cases, denounced what it called an "interference with justice".
Bouba Ali Hassan, arrested at his office last Friday was due to appear before judges "but the unit handling his transfer was prevented from going to his place of detention," the court said.
"He was then escorted by the national police to his house," it added.
The court said it was an attack on the independence of the judiciary and sought "the backing of the government in the execution" of its orders.
The Central African Republic, the second least developed country in the world according to UN rankings, was plunged into a bloody civil war after a coup in 2013.
Before he entered politics in 2017, Hassan was number two in an armed group called the Union for Peace in Central Africa (UPC).
American NGO the Sentry has said Bouba and UPC leader Ali Darassa were directly responsible for a November 2018 attack on a displacement camp that killed 112 villagers, including 19 children.
The Special Criminal Court accused him of war crimes and "crimes against humanity through murders, inhumane acts" and "cruel treatment like torture".
At the time of the 2018 attack, Hassan was special adviser to President Faustin Archange Touadera, who came to power in 2016 and whose government had started integrating rebel figures in a bid to divide the opposition.
The conflict has calmed over the past three years, although large swathes of territory remain outside central government control.
The UPC expelled Hassan in January 2021, as the rebel group temporarily joined a new rebel coalition against Touadera.