AT&T Inc and Sprint Nextel Corp asked a U.S. court on Tuesday to delay hearings in their private litigation over whether the telecommunications giant can buy T-Mobile USA, and the judge promptly agreed.

The request was similar to one that AT&T and the Justice Department made on Monday regarding the government's antitrust suit, which U.S. District Judge Ellen Huvelle also promptly signed.

An identical request was agreed in a case against AT&T brought by small regional phone company C Spire Wireless.

AT&T's agreement to delays in the cases, after previously insisting on expediting them to prevent Deutsche Telekom AG's T-Mobile USA from deteriorating in limbo, have led to pessimism that the $39 billion deal will be completed.

AT&T has also set aside $4 billion in reserves for what could eventually be a $6 billion deal breakup payment to T-Mobile.

AT&T and Sprint asked for the next hearing in the case to be January 18, at 2 p.m. EST (1900 GMT), the same time as the next hearing in the Justice Department's case against AT&T.

Huvelle has ordered AT&T and T-Mobile USA to tell the court by noon on January 12 whether they plan to continue to pursue their agreed deal or an amended one and to give an update on their plans for seeking necessary approval from the U.S. Federal Communications Commission.

Both the Justice Department and the FCC have objected to the deal on the grounds that it would hurt competition in the U.S. wireless market. The purchase of No. 4 U.S. mobile operator T-Mobile USA would vault No. 2-ranked AT&T into first place in the U.S. market.

The cases before the court are USA v. AT&T, T-Mobile USA Inc and Deutsche Telekom AG, case No. 11-1560; Sprint Nextel Corp v. AT&T Inc et al, No. 11-1600 and Cellular South (C Spire) v. AT&T, No. 11-1690. All are before the U.S. District Court for the District of Columbia.

(Reporting by Diane Bartz; Editing by Tim Dobbyn)