(CNN) -- Judges at the International Criminal Court have ordered the release of a Congolese militia chief who used child soldiers in the Democratic Republic of the Congo's civil war.
Sonia Robla, a court spokeswoman, said the decision was rendered Thursday after the prosecution refused to identify the identities of two witnesses during proceedings last week in the case of Thomas Lubanga Dyilo.
Lubanga has been accused of conscripting children under the age of 15 into the Patriotic Forces for the Liberation of Congo and "using them to participate actively in hostilities in Ituri, a district of the eastern province of the Democratic Republic of the Congo." The activity is for the period between September 2002 and August 2003.
Last week, she said, judges asked the prosecution to release the names of two witnesses. But citing a threat to the security of the witnesses if they disclosed the identities, the prosecution refused. Robla said the judges then imposed a stay of proceedings and ordered Lubanga's release Thursday.
Lubanga won't be freed "immediately" because there are five days in which the prosecution can appeal the decision.
"If it is filed, there won't be a decision on the appeal for about a few weeks," Robla said.
"Even if the appeal is rejected, Mr. Lubanga's release can only take place when the necessary arrangements are in place to transfer Mr. Lubanga to a state that will receive him, which could take weeks or months."
Lubanga's trial was the first launched by the International Criminal Court at The Hague in the Netherlands last year.
"Lubanga's armed group recruited, trained and used hundreds of young children to kill, pillage and rape. The children still suffer the consequences of Lubanga's crimes. They cannot forget what they saw, what they suffered, what they did," ICC chief prosecutor Luis Moreno-Ocampo said as the trial opened.
Lubanga pleaded not guilty.
The ICC, which was launched in 2002, was formed to try "persons accused of the most serious crimes of international concern," namely genocide, crimes against humanity and war crimes.