President Obama on Wednesday outlined a broad proposal around gun control, imploring Congress to ban the sale of military-style assault weapons and to institute universal background checks for all gun buyers. Obamas recommendations came from a task force led by Vice President Joe Biden.

Obama is asking Congress to implement mandatory background checks for all gun purchases, including private sales; reinstate a ban on some assault-style weapons; ban high-capacity magazines holding more than 10 rounds; and crackdown on illicit weapons trafficking.

Also included are new initiatives for school safety, including a call for more federal aid to states for hiring so-called school resource officers (police), counselors and psychologists, and improved access to mental health care.

I intend to use whatever weight this office holds to make them a reality,” said Obama, flanked by schoolchildren during an emotional ceremony in an auditorium next to the White House. “If there’s even one life that can be saved, then weve got an obligation to try.”

The audience also included relatives of some of the 20 first-graders who were killed along with six adults by a gunman on Dec. 14 at Sandy Hook Elementary School in Newtown, CO. Obama noted that more than 900 Americans had been killed by guns in the month since those shootings.

Following the ceremony, Obama signed 23 executive actions that took effect immediately and did not require congressional approval. Those measures will increase enforcement of existing laws, allow federal agencies to research gun violence, and encourage states to supply more information for federal background checks. More sweeping changes will require congressional action, and some Republicans quickly rejected Obamas call for an assault weapons ban.

The most controversial proposal is one that would ban certain assault rifles, and limit gun magazines to 10 rounds. Such a ban was put in place in 1994 but it was not renewed a decade later.

Obamas plan would enhance background checks by requiring all those who buy a gun to be checked for things like a history of mental health issues. Right now, those who purchase guns from licensed dealers have to undergo such checks, but those who buy them from unlicensed dealers do not. By some measurements, about 40 percent of guns are purchased without the buyer going through a background check.

Some Republicans swiftly rejected Obamas call for an assault weapons ban. The National Rifle Association released an ad Wednesday that called Obama a hypocrite because his daughters are protected by gun-carrying Secret Service agents.