(Adds more details about conference) July 28 (Reuters) - Federal Reserve Chair Jerome Powell said on Wednesday he is in the process of writing a speech to be delivered at the annual Jackson Hole conference of central bankers next month, but he declined to say what his remarks will focus on. Powell announced the speech while responding to a question during a news conference about whether the U.S. central bank will provide more details about the future pace of its asset purchases during the Aug. 26-28 conference in Jackson Hole, Wyoming. “We haven’t made any decisions about the timing,” Powell said, adding that Fed officials made their first real “deep dive” into discussions about the timing, pace and composition of future asset purchases during the two-day policy meeting that ended on Wednesday. “There’s nothing I can say about Jackson Hole,” Powell said. “I am going to give a speech but I wouldn’t want to say what will be in there at this point.” The Kansas City Fed announced in May that it will hold “a modified, in-person program” for this year’s Jackson Hole conference. The regional Fed bank said at that time it anticipated providing notice on keynote speeches closer to the event. (Reporting by Jonnelle Marte; Editing by Leslie Adler and Paul Simao) Our Standards: The Thomson Reuters Trust Principles.