CloudKit and Background tasks

Hi.
Didn't find the answer in the documentation. Are CloudKit procedures executables in background tasks ?
I'm trying to do :
"[privateDatabase fetchRecordWithID:myMasterRecordID completionHandler:^(CKRecord *myMasterRecord, NSError *error) { ... }]"
but it returns a record only when the app is active. In background task, it does nothing and waits until app is active.
Thanks for you answer.
Best
Claude