The deadly shooting at a Connecticut elementary school on Friday is likely to force Congress to consider major gun control legislation for the first time in nearly two decades, though it will be difficult for lawmakers to approve any new restrictions.

The House and Senate last debated a significant gun bill in 1994, when Democrat Bill Clinton was president and  Democrat Tom Foley was running the House. After a series of mass shootings over the previous few years, including at a restaurant in Texas and on the Long Island Railroad in New York, Congress approved a federal ban on assault weapons that prohibited the sale of 19 types of weapons and others that include assault-style features, like pistol grips.

But the ban expired 10 years later, in 2004, and has never been renewed by Congress, primarily because of opposition from Republicans and Democrats from pro-gun states like West Virginia and Pennsylvania. Many Democrats lost their seats in 1994, in part, because they supported the ban and when the Senate tried to reinstate the ban in 2004, it was defeated 90-8.

Since then, the only gun legislation approved by Congress was a 2005 requirement that gun dealers include trigger locks on the guns they sell.

But with dozens murdered in Friday's shooting spree, most of them children between the ages of 5 and 10, it will be next to impossible for President Obama and Congress to sidestep consideration of a new assault weapons ban, say gun-control advocates.

Friday's shooting follows a series of mass slayings this year, including attacks on a religious school in California (April), a movie theater in Colorado (July), a Sikh temple in Wisconsin (August) and a shopping mall in Oregon (Dec. 12).

"This is now an unavoidable debate and it is time for President Obama to lead," Joshua Horowitz, executive director of the Coalition to Stop Gun Violence, which estimates there is a mass shooting spree about every three months. "It is time for action and that is what we expect."

Despite the fears of gun-rights advocates that Obama would seek severe gun controls - a fear that led to record gun sales since Obama took office - the president didn't push any new gun laws in his first term. Immediately after Friday's massacre, however, the president suggested he would push such legislation in his second term.

"We have to come together," he said, "and take meaningful action to prevent more tragedies like this. Regardless of the politics."

Gun-control advocates say the new Congress will likely consider at least two proposals when it convenes in January. One would revive the assault weapons ban and expand it to include additional types of weapons. Another would expand the use of criminal background checks on gun buyers. About 40 percent of current gun sales, including gun-show sales, don't require background checks.

It's not clear that any new restrictions would pass, though gun-control advocates say the expanded background checks, which failed in the past, has a better chance.

Shortly after news of Friday's shootings broke, Democratic gun-control advocates began to push for legislation, while Republicans largely remained silent on the issue.

"Americans are sick and tired of these attacks on our children and neighbors and they are sick and tired of nothing being done in Washington to stop the bloodshed," said Sen. Frank R. Lautenberg, D-N.J.