WASHINGTON, Oct 27 (Reuters) - T-Mobile US Inc on Monday posted lower-than-expected quarterly earnings, as the company faced stiff competition from its rivals.

T-Mobile reported a third-quarter loss of 12 cents per share, up from a loss of 5 cents per share a year earlier.

Revenue rose 10 percent to $7.35 billion.

(Reporting by Marina Lopes; Editing by Lisa Shumaker)