President Barack Obama will ask Congress for authority to merge the U.S. trade and commerce agencies, a White House official said on Friday.

Obama was set to announce the request, meant to reduce costs and make export promotion more efficient, in a late morning address at the White House.

Some senior lawmakers have expressed concern about folding the office of the U.S. Trade Representative into a broader Commerce Department for fear it would lose its nimbleness. (Reporting by Laura MacInnis, Editing by Vicki Allen)