NEW YORK, Nov 4 (Reuters) - AT&T Inc expects to close its proposed $39 billion purchase of T-Mobile USA in the first half of 2012 because it is still fighting for U.S. regulatory approval.

The company had said when it announced the deal in late March that it expected it to close in around 12 months, implying a close around the end of the first quarter of 2012.

The disclosure of the new target closing date was in the company's quarterly filing with the Securities and Exchange Commission on Thursday.

The Department of Justice had sued in late August to block the deal arguing that it would hurt competition in the U.S. wireless market.

A February 13, 2012, trial date has been set for the Justice Department case against AT&T.

The company is looking to avoid a court battle by exploring ways to make the deal more acceptable to regulators with conditions such as asset divestitures.

AT&T would vault from second place to first place in the U.S. mobile market if it succeeds in buying No. 4 U.S. operator T-Mobile USA -- a unit of Deutsche Telekom.

Rival Sprint Nextel has opposed the deal and sued to block it. Earlier this week a federal judge ruled that Sprint could pursue part of its lawsuit.

The case is Sprint Nextel Corp v. AT&T Inc et al in the U.S. District Court for the District of Columbia, no. 11-1600

For AT&T: Mark Hansen, Michael Kellogg, and Steven Benz of Kellogg, Huber, Hansen, Todd, Evans & Figel, Randolph Smith, Shari Lahlou and Kathryn Kirmayer of Crowell & Moring, and Richard Rosen and Donna Patterson of Arnold & Porter.

For Sprint: Steven Sunshine, Gregory Craig and Tara Reinhart of Skadden, Arps, Slate Meagher & Flom.

(Reporting by Sinead Carew)

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