July 28 (Reuters) - Federal Reserve Chair Jerome Powell said on Wednesday that he is in the process of writing a speech to be delivered at the annual Jackson Hole conference of central bankers taking place next month, but he declined to say what his remarks will focus on. Powell responded to a question during a news conference after the end of the Fed’s latest two-day policy meeting about whether the central bank will provide more details about the future pace of its asset purchases during the upcoming conference. The Kansas City Fed, which organizes the conference held in Jackson Hole, Wyoming, does not release the agenda until after the conference starts. (Reporting by Jonnelle Marte; Editing by Leslie Adler) Our Standards: The Thomson Reuters Trust Principles.