ISTANBUL (Reuters) - Turkey s President Tayyip Erdogan said on Wednesday that the United States could no longer be a mediator in efforts to end  Israeli-Palestinian conflict after its decision to recognize Israel as the capital of Israel.   From now on, it is out of the question for a biased United States to be a mediator between Israel and Palestine, that period is over,  Erdogan told a news conference after a meeting of the Organization of Islamic Cooperation in Istanbul.  We need to discuss who will be a mediator from now on. This needs to be tackled in the UN too,  Erdogan said. 