WASHINGTON, July 23 (Reuters) - Three Democrats on the

House Energy and Commerce Committee raised serious concerns

about T-Mobile's involvement in the Trump

Organization's self-branded mobile service and a $499 smartphone

dubbed Trump Mobile.

Representative Frank Pallone, the ranking member of the

committee and two other committee members, asked T-Mobile CEO

Mike Sievert to answer questions about the company's dealings

with the Trump organization. "We are specifically concerned that

T-Mobile's business relationship with the Trump Organization -

while Donald Trump is serving as President of the United States

- presents a conflict of interest that will harm the American

people," they wrote in a letter Wednesday.