Law enforcement officials, mayors from across the country and supportive congressional lawmakers are also expected to attend.
According to a lobbyist briefed on Tuesday, Obama would present a three-part plan focused on gun violence, education and mental health.
The president was to call for a focus on universal background checks. Some 40 percent of gun sales take place without background checks, including those by private sellers at gun shows or over the Internet, according to the Brady Campaign to Prevent Gun Violence.
He was to call for banning assault weapons and limiting ammunition magazines to 10 rounds or fewer, and also propose a federal statute to stop “straw man” purchases of guns and crack down on trafficking rings. He would order federal agencies to conduct more research on gun use and crimes, something Republican congressional majorities have limited through language in budget bills, the lobbyist said.
Obama has pledged urgent action to prevent future mass shootings, and his plan — coming just one month after the Newtown attacks — is swift by Washington standards.
His framework is based on recommendations from US Vice President Joe Biden, who led a wide-ranging task force on gun violence. Beyond the gun control measures, Biden also gave Obama suggestions for improving mental health care and addressing violent images in video games, movies and television.
The vice president’s proposals included 19 steps that could be achieved through executive action.