Verizon Wireless and rival AT&T, the top two mobile carriers in the U.S., announced Thursday they will start selling Apple iPads at their respective stores nationwide on Oct. 28 even as Apple Inc. tries to fend off competition from other tablet makers.

Verizon Wireless, which is co-owned by Verizon Communications and Vodafone Group, is selling a 16GB iPad bundled with the Wi-Fi device MiFi 2200 for $630. A 32GB and 64GB versions will sell for $730 and $830, respectively. Without MiFi, the price is $499.

A $20 per month iPad plan allows subscribers usage of up to 1GB. A 10GB usage costs $80 monthly.

AT&T offer $629 iPad on a $15 per month plan for up to 250 megabytes of data transfer. A 2GB usage plane cost $25.

While AT&T has provided wireless service to iPads since its debut in April, Verizon hopes to level the playing field by selling the tablet computer combined with a data plan at its 2,000 stores nationwide.

Verizon's move is also a prelude to a tie-up with Apple that will see an iPhone version working on the former's mobile service network, according to sources. An agreement to this effect will end AT&T's exclusive network service for iPhone users in the U.S.

For its part, two mobile carriers supporting iPhones will bolster Apple's competitive edge over rival tablets of Samsung Electronics Inc., Dell Inc. and Research In Motion Ltd.