Media playback is unsupported on your device Media caption Democratic Congressman Bobby Scott says he believes reforms on background checks and mental health provision are likely

US President Barack Obama is expected on Wednesday to unveil wide-ranging measures aimed at curbing gun violence.

The proposals could echo measures, considered the toughest in the nation, passed in New York state on Tuesday.

Mr Obama has said he favours bans on assault weapons and high-capacity ammunition magazines, as well as broader background checks.

The US gun control debate has been revived by last month's mass shooting at a school in Newtown, Connecticut.

There, a gunman shot dead 27 people, including 20 children and his own mother.

Stiff opposition ahead

At 11:55 EST (16:55 GMT) on Wednesday, Mr Obama is expected to unveil the new proposals at the White House, flanked by children who wrote him letters after the Newtown shooting.

Mr Obama has already acknowledged his proposals will face stiff opposition in Congress. But he is said to be weighing as many as 19 specific measures he could take through unilateral executive action.

Media playback is unsupported on your device Media caption The parents of Dylan Hockley, killed at Sandy Hook, spoke to the BBC

These could include tougher punishment of gun trafficking, aggressive prosecution of people who lie on background checks, and an end to limits on government research into gun violence.

The nation's top gun lobby, the National Rifle Association (NRA) says it will fight any attempts to limit access to guns or ammunition.

In the days after the Newtown shooting, the NRA proposed stationing armed guards in every school in America. The group says it has signed up more than 100,000 members since the massacre.

On Wednesday, the group released a web advert attacking the president as "an elitist hypocrite" because his daughters are protected by armed guards at their school in Washington DC. But, the ad claims, he opposes armed guards in every school and favours "gun-free" school zones.

Mr Obama has said he is "sceptical" that putting more guns in schools is the "only answer", but he has not taken a stronger position on the NRA's proposal, nor commented on gun-free school zones.

Gun attitudes altered

Analysis Even before his second term begins, Barack Obama is about to throw down a big gauntlet. No-one expected gun control to be so high on his list of priorities, but the killings at Newtown seem to have changed everything. The president knows he faces a daunting challenge - there's little appetite in Congress for major gun control legislation. But Mr Obama seems determined to try to shame Congress into action. He'll be surrounded by children when he unveils his plans, a device that could prove as controversial as the measures themselves. He may cite the example of New York state - which has just passed one of the toughest gun ownership laws in the country - as evidence that changes can be made to the law. But opponents of new legislation are mobilising and gun sales have soared since Newtown. For the first time in almost 20 years, the stage is set for a bitter fight over America's gun laws.

On Tuesday, the New York state legislature comfortably passed the first gun control law since the shootings in Newtown. Supporters said the state's firearms restrictions were now the tightest in the nation.

"Common sense can win," New York Governor Andrew Cuomo, a Democrat, said.

"You can overpower the extremists with intelligence and with reason and with common sense."

The New York measures include a wider ban on assault weapons, a law limiting high-capacity ammunition magazines, and provisions to keep guns from mentally ill people who make threats.

Some gun owners will also have to register them with authorities.

According to a Washington Post-ABC News poll released on Monday evening, about half of Americans say they have grown more supportive of gun control measures since the Newtown shooting.

The poll found 58% of respondents back a ban on the most powerful rifles.