WASHINGTON, April 25 (Reuters) - The U.S. Federal

Communications Commission said on Thursday it will approve the

T-Mobile US Inc ( TMUS ) deal to buy Ka'ena Corp, the owner of

budget service provider Mint Mobile, for up to $1.35 billion.

The FCC cited T-Mobile's voluntary agreement to implement a

60-day unlocking period for all Mint Mobile and Ultra Mobile

devices activated on the T-Mobile network before and after the

closing.

The FCC said the agreement will make it easier for Mint

Mobile and Ultra Mobile customers to switch service providers.