* Six Red Cross workers and local volunteer seized on Sunday
* ICRC says four freed, awaits word on remaining three
* Says abduction disruptive and puts operations in jeopardy
* Millions of Syrians depend on humanitarian aid
By Oliver Holmes and Stephanie Nebehay
BEIRUT/GENEVA, Oct 14 (Reuters) - Four of seven aid workers abducted in Syria have been freed, the Red Cross said on ...