By David Shepardson and Alexander Cornwell WASHINGTON/DUBAI (Reuters) -United Airlines and Dubai's Emirates are set to announce a codeshare agreement in the coming weeks, sources told Reuters. United on Tuesday sent an invitation to reporters to a "special event" on Sept. 14 titled "Come fly with us" with Chief Executive Scott Kirby and Emirates President Tim Clark in Washington. The Air Current reported the expected announcement earlier. United did not offer additional comment. An Emirates spokesperson confirmed the airlines will make "a joint announcement" on Sept. 14 in Washington, declining to elaborate. After receiving government approvals, a codeshare would allow both airlines' customers access to additional destinations that each do not currently serve. The agreement is likely to help United better compete for customers flying to the Gulf region.