Anti-gun protest planned at Newtown-area Walmart DANBURY, Connecticut (Reuters) - Gun-control advocates are planning a rally outside a Walmart store near Newtown, Connecticut, on Tuesday to demand the largest U.S. retailer stop selling assault weapons. The rally is planned for a Walmart in a Danbury shopping center, which is eight miles from the Newtown elementary school where a gunman opened fire on December 14, killing 20 first graders and six educators. The group SumofUs plans to deliver a letter of protest to Walmart, which it says has been signed by 250,000 people. Lori Haas, whose daughter was injured in the 2007 shooting at Virginia Tech, and Pam Simon, who was wounded in the 2011 shooting in Tucson, Arizona, that also critically injured former Congresswoman Gabrielle Giffords, are expected to appear. Wal-Mart Stores Inc is the nation's largest gun retailer, but the Danbury location does not sell lethal firearms. The killings plunged the rural New England town of 27,000 into grief along with much of the nation and prompted President Barack Obama to form a task force headed by Vice President Joe Biden to find ways to curb gun violence. Biden is due to submit recommendations to the president as early as Tuesday. Reporting By Edith Honan; Editing by Maureen Bavdek