Google on Tuesday launched a new model of its own Nexus One smart phone that is compatible with AT&T's 3G wireless network in the United States, which is seen as the Internet search company's latest attack against rival Apple.

Starting from Tuesday, the new model can be purchased from Google's online store without a service plan for 529 U.S. dollars.

In addition to AT&T's 3G network, the new model can also run on the 3G network of Rogers Wireless in Canada, Google said in a statement posted on its online store.

Google launched the Nexus One in early January this year. The original model works on T-Mobile's 3G network in the U.S., but can only access AT&T's slower network as the wireless carrier uses different 3G frequencies than T-Mobile.

AT&T is the exclusive U.S. 3G carrier of iPhone, Apple's popular handset.