ORLANDO, June 14, 2016 -- Photo taken with mobile phone on June 13, 2016 shows customers selecting gun at a shop in Orlando, the United States. The American society has been buzzing with measures to prevent further gun-related violence in the United States, after a shooting spree in an Orlando nightclub left 49 dead and 53 wounded on Sunday. (Xinhua/Yin Bogu)

ORLANDO, the United States, June 16 -- U.S. President Barack Obama on Thursday again urged Republican-controlled Congress to pass stricter gun control laws during his visit to Orlando in the wake of the country's deadliest mass shooting incident.

"Those who were killed and injured here were gunned down by a single killer with a powerful assault weapon," Obama told reporters. "The motives of this killer may have been different than the mass killers in Aurora, or Newtown. But the instruments of death were so similar. Now another 49 innocent people are dead. Another 53 are injured. Some are still fighting for their lives."

At least 49 people were killed and 53 others wounded, including a police officer, early Sunday morning in a shooting spree at a popular LGBT nightclub in Orlando, Florida. It was the deadliest terror attack in the U.S. history since 9/11 in 2001.

The gunman, identified by authorities as Omar Mateen of Port St. Lucie, Florida, was found dead inside the nightclub after a shootout with the police.

"I truly hope that senators rise to the moment and do the right thing. We can stop some tragedies. We can save some lives. If we don't act, we will keep seeing more massacres like this," said Obama.

Following the 2012 school mass shootings in Newtown, Connecticut, which claimed 26 lives, including 20 children, the Obama administration initiated but failed to push stronger gun control laws.

The laws, whose sections included expanded background checks and bans on assault weapons, were stymied in Congress after staunch opposition from Republican lawmakers and gun-rights lobby groups.

During his presidency, Obama presided over more than a dozen of high-profile mass shootings, and in an interview last year he called the failure to reform U.S. gun laws "one of the greatest frustrations" of his presidency.

"If you ask me where has been the one area where I feel that I've been most frustrated and most stymied, it is the fact that the United States of America is the one advanced nation on Earth in which we do not have sufficient common-sense gun safety laws, even in the face of repeated mass killings," Obama told BBC in an interview in July, 2015.