NEW YORK » The first two phones to run on AT&T’s new high-speed data network will go on sale Sunday.

The phones are the HTC Vivid and the Samsung Galaxy S II Skyrocket. Both are big touchscreen smartphones that run Google Inc.’s Android software. They’ll cost $200 and $250 respectively, with a two-year service contract requirement.

Dallas-based AT&T Inc. is building a network based on Long-Term Evolution, or LTE, technology. It offers higher data speeds and offloads traffic from the current data network.

The network covers Atlanta, Chicago, Dallas-Fort Worth, Houston and San Antonio, Texas, so far. On Sunday, it will be expanded to Boston, Washington, Baltimore and Athens, Ga. By the end of the year, the goal is to have the network live in 15 cities.

The two LTE phones can also use AT&T’s regular, nationwide data network. They will be sold with data plans that are identical to those required for other smartphones. For $15 per month, subscribers get 200 megabytes of data usage per month. For $25, the limit is ten times higher, or 2 gigabytes per month.

So far, the only devices that have been able to use AT&T’s LTE network are plug-in data sticks for laptops.

Verizon Wireless has been selling Android phones for its LTE network since this spring.