President Barack Obama will reveal the details of how the U.S. will address gun violence on Wednesday, the White House said Tuesday, while New York's lawmakers agreed to pass the toughest gun control law in the nation and dared other states to do the same.

The Obama administration has been moving quickly on the issue before the shock fades over last month's school shooting in Connecticut, which Obama has called the worst day of his presidency.

The White House said Obama would appear Wednesday with children who wrote letters to him after the shooting — a clear attempt to appeal to the public as opposition grows among pro-gun groups and Americans who fear their weapons will be taken away. The U.S. has the highest rate of gun ownership of any country in the world.

Obama has acknowledged a tough fight ahead in a deeply divided Congress, whose support would be needed to pass the most sweeping changes under consideration, including a ban on assault weapons, limits on high-capacity ammunition magazines like the ones used in the Connecticut shooting and background checks for anyone seeking to purchase a gun. The gun in last month's shooting was legally purchased.

Obama has said lawmakers will have to "examine their own conscience." But the gun issue will have to compete for Congress' time in coming weeks with several looming fiscal issues, and Republican leaders have said action on guns will have to wait.

Obama also can use his executive powers to make some changes without the need for Congress' approval.

But the focus on stricter gun controls has some pro-gun groups on the defensive. The head of a weapons industry group, which is based in the town where the Connecticut shootings occurred, said Tuesday that law-abiding gun owners didn't cause the gunman to attack, and neither did the industry.

National Shooting Sports Foundation chief Steve Sanetti called weapons manufacturers, sellers and owners "misunderstood" in comments prepared for his speech on the state of the profitable $4.1 billion industry.

"You didn't cause the monstrous crime in Newtown, and neither did we," Sanetti said.

The most contentious elements of the Obama administration's plans also face intense opposition from the influential National Rifle Association, which enjoys strong support from Republicans as well as several Democrats and is known to punish politicians who stray from its point of view.

The assault weapons ban, which Obama has long supported, is expected to face the toughest opposition in Congress, which passed a 10-year ban on the high-grade, military-style weapons in 1994. Supporters didn't have the votes to renew it once it expired.

States and cities have been moving against gun violence as well. In New York, Gov. Andrew Cuomo was poised to sign into the law the most restrictive gun law in the nation.

"This is a scourge on society," Cuomo said Monday night. "At what point do you say, 'No more innocent loss of life'?"

The New York bill had bipartisan support, with the leader of the Republican-held state Senate saying it does not infringe on the Constitution's Second Amendment of the U.S. Constitution, which guarantees the right of citizen to bear arms.

The New York measure calls for a tougher assault weapons ban and restrictions on ammunition and the sale of guns. It also would create a more powerful tool to require the reporting of mentally ill people who say they intend to use a gun illegally, and it would address the unsafe storage of guns.

The assault weapons currently being debated are generally military- or police-style semi-automatic weapons that are shorter than a conventional rifle. They often have 10- to 30-round magazines that can be easily replaced when empty.

At the national level, advocacy groups also have been pushing Obama to order the Justice Department to crack down on those who lie on background checks; only a tiny number are now prosecuted. Such a step has support from the NRA, which has consistently argued that existing laws must be enforced before new ones are considered.

The Brady Campaign to Prevent Gun Violence says some 40 percent of gun sales happen with no background checks, such as at gun shows and by private sellers over the Internet or through classified ads.

Obama also could take steps ordering federal agencies to make more data on gun crimes available and conduct more research on the issue, something Republican congressional majorities have limited through language in budget bills, advocates said.

The president's proposals are also expected to include steps for improving school safety and mental health care, as well as recommendations for addressing violence in entertainment and video games.