Decides to call upon the parties concerned to implement immediately Security Council resolution 338 (1973) of 22 Oct. 1973; to renew the mandate of the UN Disengagement Observer Force for another period of six months until 31 May 1988 and to request the Secretary-General to submit, at the end of this period, a report on the developments in the situation and the measures taken to implement Security Council resolution 338 (1973).