FOUR young illegal immigrants who were transferred from Victoria Prison last week on orders from the Governor have been released from custody. A government spokesman confirmed last night that the girls aged from 14 to 17, who had been held for up to nine months, had been released from the care of the Social Welfare Department yesterday. The girls were moved from Victoria Prison to the Ma Tau Wai Girls' Home after it was learned they were part of a larger group of girls under the age of 21 who were classed as juveniles but were in the custody of the Correctional Services Department. ''The four girls have been released on their own recognisance. They are now at liberty save for a requirement that they must report at intervals to the police,'' the spokesman said. ''The detention of these young girls in Ma Tau Wai was not intended to be a permanent solution. ''It was a temporary measure pending further examination of the case. ''An arrangement has now been put in place which has regard both to the age of the girls and their individual rights and the need to retain them in Hong Kong as prosecution witnesses.'' Twelve others under 21 remain in custody as an internal review into their detention continues.