Serbian President Slobodan Milosevic said in a statement today that he had persuaded the Bosnian Serbs torelease the 256 UN peacekeepers still held hostage. The statement does not say when the hostages will be set free. Milosevic has sent an aide to the Bosnian Serb stronghold of Pale to join the Greek foreign and defense ministers who are thereto try to negotiate a quick release. Despite Milosevic's assurances, the Bosnian Serbs appear to be digging in their heels, saying they won't release any more hostages without a UN pledge to halt air strikes. In Sarajevo, theBosnian Serb troops continue to harass UN peacekeepers. Three Canadians were taken into custody today; they were already counted among the hostages since their movements had been closely restricted.