Washington (CNN) -- President Barack Obama will unveil Wednesday a package of gun control proposals that, according to a source, will include universal background checks and bans on assault weapons and high-capacity magazines.
Obama and Vice President Joe Biden will announce the proposals, White House spokesman Jay Carney told reporters on Tuesday.
They will be joined by a group of children who wrote letters to the president in the aftermath of the December 14 shooting rampage by a lone gunman who killed 20 students and six adults at a Newtown, Connecticut elementary school, Carney said.
Obama will propose legislative steps he previously has backed, such as a ban on assault weapons, restrictions on high-capacity ammunition magazines and strengthening federal background checks of people attempting to buy guns, according to Carney.
The president also will push for other steps that could include executive actions on his part that don't require congressional approval, Carney noted.
More specifically, the source -- an official familiar with the process -- said the president's proposal will press for a ban on high capacity magazines with more than 10 rounds, universal background checks and a request that funds be made available to help treat mental illness and provide schools with support to enhance their safety.
Biden led a panel assembled by Obama to examine gun control steps after the Newtown shootings, which sparked a fierce public debate over how to prevent such mass killings with guns.
Opponents led by the powerful National Rifle Association promise a political fight against gun control measures that they say will violate the constitutional right to bear arms.
An NRA spokesman said Tuesday the group has experienced what he called an "unprecedented" spike in membership numbers since new calls for gun control began in the past month.