Obama renews call for gun restrictions

"My administration is taking a series of actions right away - from strengthening our background check system, to helping schools hire more resource officers if they want them, to directing the Centers for Disease Control to study the best ways to reduce gun violence," Obama said in his weekly radio and Internet address.

"But the truth is," he added, "making a real and lasting difference also requires Congress to act - and act soon."

Obama signed 23 executive orders on Wednesday, using his presidential power in a swift effort to stem a rash of gun violence in the wake of last month's massacre of 20 children and six adults at Sandy Hook Elementary School in Newtown, Connecticut, and other recent mass shootings.

At the same time, he challenged Congress to enshrine enduring reforms into law, including renewing and bolstering a ban on assault weapons, and closing loopholes that permit 40 percent of gun sales to take place without background checks.

Currently, licensed gun sellers are required to run background checks on customers, but private sales of firearms benefit from a loophole.

The president also called for tougher punishment of people who buy guns only to re-sell them to criminals.

Prominent Republicans rejected Obama's plan out of hand, accusing him of attacking the right to bear arms enshrined in the Second Amendment to the Constitution. But the president denied his goal was to hollow out this fundamental right.

"Like most Americans, I believe the Second Amendment guarantees an individual right to bear arms," he said in the address. "We have a strong tradition of gun ownership in this country, and the vast majority of gun owners act responsibly."

But Obama added he believed Americans can at the same time respect the Second Amendment and prevent irresponsible, law-breaking people from causing harm on a massive scale.