German newspaper Handelsblatt today identified AT&T, Kirkland-based Clearwire and MetroPCS as potential partners for T-Mobile USA as the Bellevue-based company's parent, Deutsche Telekom, looks to finance a network upgrade for its U.S. subsidary.

Reuters quotes two anonymous sources who say Deutsche Telecom is "keeping its options open for its U.S. business and is not close to making a decision."

T-Mobile, the No. 4 wireless provider in the country, is looking for ways to improve its network and compete more effectively against rivals including AT&T, which has exclusive rights to the iPhone in the United States.

Reuters quotes Hamid Akhavan, Deutsche Telekom's chief operating officer, saying that the company was still committed to the U.S. market, and that it was "quite optimistic that this trend can be reversed." AT&T, Clearwire and Deutsche Telekom declined to comment in response to inquiries from news site Fierce Wireless.