Media playback is unsupported on your device Media caption President Obama on why he has asked Joe Biden to lead the response

US President Barack Obama has called for "concrete proposals" on gun control by the end of January, saying "words need to lead to action".

In remarks at the White House, Mr Obama said Vice-President Joe Biden would lead an exploration of options after a mass school shooting in Connecticut.

There have been calls for gun law reform after 26 children and teachers died at Sandy Hook School in Newtown.

The president said a "majority of Americans" back changes to some laws.

Those include the renewal of an assault weapons ban, limits on high-capacity ammunition magazines and an end to loopholes allowing gun purchases with no background checks, Mr Obama said.

School stays shut

Funerals were held for more victims of the shooting, including teacher Victoria Soto and three students: Daniel Barden, seven, Caroline Previdi, six, and Charlotte Bacon, six.

Media playback is unsupported on your device Media caption Some gun shops in the US have seen a rise in sales as people try to beat any new laws

A wake was held for Dawn Hochsprung, the school's principal, who is reported to have rushed towards the gunman with the school psychologist Mary Sherlach before they were both killed.

The rest of Newtown's students returned to classes on Tuesday, as grief counsellors and police were posted to schools.

But for pupils at Sandy Hook School, classes will resume on 2 January at Chalk Hill School in the nearby town of Monroe.

Mrs Robinson said pupils and parents would be invited to visit the new facility later this week.

NRA response

Meanwhile, Mr Obama urged Congress to hold votes on gun control measures when it reconvenes in the new year.

"If there is even one thing that we can do to prevent any of these events, we have a deep obligation - all of us - to try," he said.

"The fact that we can't prevent every act of violence doesn't mean we can't steadily reduce the violence."

The assault weapons ban lapsed under President George W Bush in 2004.

US gun control timeline June 1968: The assassination of Senator Robert Kennedy prompts calls for federal gun control measures

The assassination of Senator Robert Kennedy prompts calls for federal gun control measures October 1968: Gun Control Act bans the sale of firearms to certain groups, including convicted felons and minors

Gun Control Act bans the sale of firearms to certain groups, including convicted felons and minors March 1981: Attempted assassination of President Ronald Reagan: Spokesman Jim Brady is shot in the head and paralysed for life

Attempted assassination of President Ronald Reagan: Spokesman Jim Brady is shot in the head and paralysed for life 1993: The Brady Bill requires background checks of anyone seeking to buy a firearm from a licensed dealer but exempts private sales - the so-called "gun show loophole"

The Brady Bill requires background checks of anyone seeking to buy a firearm from a licensed dealer but exempts private sales - the so-called "gun show loophole" 1994: Federal assault weapons ban is passed; critics say the ban was rife with loopholes and easily evaded

Federal assault weapons ban is passed; critics say the ban was rife with loopholes and easily evaded 2004: Assault weapons ban expires; congress shows little interest in renewing it

Assault weapons ban expires; congress shows little interest in renewing it 2008: In District of Columbia v Heller ruling, the US Supreme Court finds the second amendment to the US constitution protects an individual's right to own guns for the purposes of self-defence

In District of Columbia v Heller ruling, the US Supreme Court finds the second amendment to the US constitution protects an individual's right to own guns for the purposes of self-defence 2010: In McDonald v City of Chicago, the US Supreme Court holds the second amendment applies to states, potentially weakening state gun control laws Statistics: Guns in the US Can Newtown change the gun debate? In pictures: Newtown grieves

Mr Obama has previously stated his support for a reintroduction without backing a specific move to do so before now.

Mr Biden has decades of experience as a senator and analysts say that experience could be essential to getting any changes through Congress, which has been lobbied extensively on the issue by the National Rifle Association (NRA).

The vice-president's team will include members of the Obama administration as well as representatives of outside groups.

In its first statement since the shootings, the NRA said it was "heartbroken" by the attack and would offer "meaningful contributions" to help prevent future tragedies.

There is no indication whether the NRA will join the Biden-led process.

Gun sales, including those of assault rifles, have risen since Friday, a sign that enthusiasts fear that new legislation is coming, the BBC's Paul Adams in Washington reports.

At the same time, share prices of several gun manufacturers have fallen and a private equity firm has sold its stake in the company that makes the assault rifle used at Newtown.

Some anti-gun control congressmen and senators have indicated they are prepared to consider changes to the current legislation.

Jack Kingston, a Republican congressman from Georgia who is backed by the NRA, has on Wednesday joined the ranks of lawmakers who say they would consider gun control as part of a broader effort to reduce violence.

Pro-gun Democratic senators Joe Manchin and Mark Warner have also signalled that they are reconsidering their positions.

But some House Republicans, who hold a majority in the House of Representatives have suggested that action on gun legislation was premature and that they were focused on the tragedy.

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.