WASHINGTON — The Obama administration is assembling proposals to curb gun violence that would include a ban on sales of assault weapons, limits on high-capacity ammunition magazines and universal background checks for gun buyers. The country's most powerful pro-gun group made clear its opposition to such moves. President Barack Obama has pushed reducing gun violence to the top of his domestic agenda following last month's massacre of 20 children and six adults at a Connecticut elementary school. The president put Vice President Joe Biden in charge of an administration-wide task force and set a late January deadline for proposals. Sketching out details of the plan Thursday, Biden said he would give Obama a set of recommendations by next Tuesday. The National Rifle Association, one of the pro-gun groups that met with Biden during the day, rejected the effort to limit ammunition and dug in on its opposition to an assault weapons ban, which Obama has previously said he will propose to Congress. “The vice president made it clear, made it explicitly clear, that the president had already made up his mind on those issues,” NRA president David Keene said following the meeting. “We made it clear that we disagree with them.” Opposition from the well-funded and politically powerful NRA underscores the challenges that await the White House if it seeks congressional approval for limiting guns and ammunition. The NRA and many Americans consider individual gun ownership a basic right, citing the Constitution's Second Amendment that gives citizens the right to bear arms. Gun control advocates counter that the Second Amendment never was intended to allow ordinary citizens to wield military-style weapons like the AR-15 rifle used in the Newtown massacre. Obama can use his executive powers to act alone on some gun measures, but his options on the proposals opposed by the NRA are limited without Congress' cooperation. “I committed to him I'd have these recommendations to him by Tuesday,” Biden said Thursday, during a separate White House meeting with sportsmen and wildlife groups. “It doesn't mean it's the end of the discussion, but the public wants us to act.” — AP