United States President Barack Obama made an emotional appeal on Tuesday to rein in gun violence in the country, as he teared up while remembering the fatal shooting of elementary school children in Newtown three years ago. 

Obama unveiled his executive measures that will bring in compulsory licensing for gun sellers and strict background checks for buyers. The White House had shared the planned policies on Monday. READ: Obama's planned executive actions for 'commonsense' steps on gun control

"Our inalienable right to life and liberty and the pursuit of happiness, those rights were stripped from college kids in Blacksburg and Santa Barbara and from high schoolers at Columbine, and from first-graders in Newtown," the US president said during his address in the East Room of the White House.

"Every time I think about those kids it gets me mad. And by the way, it happens on the streets of Chicago every day," he said. 

He hit out at gun lobbyists and gun proponents for stalling efforts on gun control. 

"The gun lobby may be holding Congress hostage right now, but they cannot hold America hostage."

Obama urged the US Congress to support "common-sense" gun safety measures but said until that happened he would take actions under his legal authority. 

He cited an example of Connecticut that passed a law requiring background checks and gun safety courses, stating that gun deaths decreased by 40%.

Republicans have, however, vowed to challenge Obama's executive actions in court. 

"No matter what President Obama says, his word does not trump the Second Amendment. We will conduct vigilant oversight. His executive order will no doubt be challenged in the courts," speaker of the House of Representatives, Paul Ryan said on his website

The Obama administration's policies propose a $500 million investment to increase access to mental health care, and to include information in the background check system about those prohibited from possessing a firearm for mental health reasons.

It will also focus on bringing in newer technologies to make guns safer. 

"If we can develop technology that you can't unlock your phone unless you've got the right fingerprint, why can't we do it for guns? If a child can't open a bottle of Aspirin, we should make sure that they can't pull the trigger on a gun," Obama said.