ORLANDO, the United States - The shooting massacre at a nightclub on Sunday in Orlando, Florida was the 176th mass shooting which happened in the United States in the past 168 days so far in 2016, according to the group Mass Shooting Tracker.

Unlike the Federal Bureau of Investigation, which defines the "mass shooting" as an incident where four or more people are killed in one case, the Tracker broadens the definition of the "mass shooting" to include all incidents involving four or more people being shot but not necessarily killed.

By that criteria, the Tracker reports after collecting data from news reports around the nation that the shooting carnage at Pulse, a popular LGBT nightclub, which left 50 dead, including the gunman, was the 176th mass shooting so far this year.

According to the Tracker, as of Tuesday, six more mass shootings occurred in the wake of Orlando nightclub massacre.

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 history since the 9/11 terror attacks 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.

So far, federal investigators had found no clear evidence that Mateen had been in touch with any terrorist groups before the attack.

However, according to Director of Federal Bureau of Investigation (FBI) James Comey, the authorities were "highly confident" that Mateen had been radicalized online.

Just like his previous reactions after similar mass shooting incidents in the past, US President Barack Obama this time again stressed the importance of passing stricter gun control laws on every public appearances in the wake of the incident.

His latest response came on Thursday during his visit to families of victims and survivors in Orlando, Florida.