T-Mobile, the German mobile unit of Deutsche Telekom, has been asked by a Hamburg court to change its marketing for Apple Inc.'s iPhone.

The device went on sale this month in Germany with Deutsche Telekom as its exclusive vendor.

Deutsche Telekom requires buyers to sign up to a two-year contract with its T-Mobile wireless network. As well, the iPhone contains a lock that prevents it from being used on any other network.

But the regional court in Hamburg on Tuesday temporarily prohibited T-Mobile from continuing to sell the iPhone only in combination with that two-year contract, and requested that the device be allowed to function with other networks.

A full hearing on the matter will reportedly take place in Hamburg in two weeks' time.

This could pose significant problems for T-Mobile, which fought hard to secure exclusive rights to sell the iPhone in Germany, just the way AT&T Inc. did in the U.S. and Telefonica's O2 did in Britain.

Vodafone Deutschland, a unit of Vodafone Group Plc, the world's largest mobile operator by revenue, kicked off the hostilities by filing a preliminary injunction regarding T-Mobile's marketing rights late Monday.

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