French judicial authorities have launched an investigation into new U.N. allegations of sexual abuse targeting French troops in the Central African Republic.

A French judicial source says Tuesday the Paris prosecutor's office has opened a preliminary probe into possible "sexual assaults" involving French troops in the central town of Dekoa from 2013-2015.

The source, who spoke on condition of anonymity to discuss the sensitive case, says the U.N. allegations deal with "sexual abuse and exploitation that could involve French troops with the Sangaris military force" operated by France in CAR.

The source says the new probe is not related to allegations by a U.S.-based group claiming three girls told U.N. staff they were tied up, undressed and forced to have sex with a dog by a French military commander in 2014.