President Barack Obama is due to announce that Vice-President Joe Biden will lead attempts to reform gun laws in the US. There have been widespread calls for reform following the shooting of 26 children and teachers in Sandy Hook School, Connecticut, last week.
White House officials said Mr Obama would set out the process by which his administration will move forward.
Mr Obama wants to reintroduce a ban on assault weapons.
That ban lapsed under President George W Bush in 2004 and Mr Obama has previously stated his support for a reintroduction without backing a specific move to do so before now.
The president issued a call to action at a memorial service on Sunday, promising he would “use whatever power this office holds” to prevent more multiple shootings.
An announcement is expected in the White House briefing room later on Wednesday.
Mr Biden has decades of experience as a senator and analysts say that experience could be essential to getting any changes through Congress.
Some anti-gun control congressmen and senators have indicated they are prepared to consider changes to the current legislation.
The Democratic Senator for West Virginia, Joe Manchin, said on Monday that it was time to “move beyond rhetoric”.
Mr Manchin, a gun owner and frequent hunter, said: “I don’t know anyone in the sporting or hunting arena that goes out with an assault rifle.”
Another Democrat, Senator Mark Warner, said that the “status quo isn’t acceptable” and called for “rational gun control”.
Mr Warner said he had been approached repeatedly over the weekend as people began to seek answers and solutions.
California Senator Dianne Feinstein, a well-known supporter of gun control, said on Sunday she would introduce assault weapons ban legislation when the new Congress met for the first time in January.
The White House says that Mr Obama also supports other proposed gun legislation, including restricting the sale of high-capacity ammunition clips and closing a loophole that allows gun purchases at gun shows without a background check.
School stays shut
Plans for pupils at Sandy Hook School to resume classes on Wednesday at another school have been dropped.
The Newtown Superintendent of Schools, Janet Robinson, said classes would now recommence on 2 January at Chalk Hill School in the nearby town of Monroe.
“The teachers weren’t ready, the building wasn’t ready”, Mrs Robinson said. “So we just abandoned that idea. That plan was too ambitious.”
Mrs Robinson said pupils and parents would be invited to visit the new facility later this week.