President Donald Trump on Sunday blamed “the left” for the atmosphere that he said produced the assassination of conservative commentator Charlie Kirk and told reporters that "major investigations" into left-leaning groups are underway as authorities seek a motive.

Trump spoke to reporters at Morristown, New Jersey, as federal and local officials continued to investigate the shooting at Utah Valley University that left Kirk dead last week. Tyler Robinson has been identified in reporting as the accused shooter; prosecutors and the FBI are working to determine whether the attack was politically motivated.

"The problem? Is on the left, it's not on the right, like some people like to say on the right," Trump said at the airport. "The problem we have is on the left. And when you look at the agitators, you look at the scum that speak so badly of our country, the American flag burnings all over the place, that's the left. That's not the right."

Trump said investigators have opened probes into "a lot of people that you would traditionally say are on the left," and that the inquiries are connected to the FBI's broader search for a motive in Kirk's killing. He also condemned online posts praising the attack, calling those who celebrated "sick" and "deranged." "We wouldn't celebrate if something happened on their side, and we don't," he added.

Investigators have been pursuing leads into the accused shooter's background and online activity as they seek to determine whether any organized groups or individuals contributed to the motive or planning of the attack. Law enforcement officials have not publicly identified a definitive motive.

Kirk, a conservative commentator and founder of Turning Point USA, was shot on a university campus where he was appearing last week. Authorities have said the case remains under active investigation by local police and federal agencies, including the FBI. The investigation is being handled with standard procedures to determine intent, association and responsibility.

Several people who posted celebratory messages about the killing on social media have, according to reporting, faced employment consequences or removal from positions. Company statements and media reports have said some individuals were fired or suspended after public posts praising the shooting were brought to employers' attention.

The shooting has intensified debate in political circles about online rhetoric and the potential real-world effects of harassment and violent language. Trump used his remarks to argue that left-leaning speech and actions contribute to a climate of hostility that he linked to the violence that killed Kirk.

Law enforcement officials cautioned that the investigation is ongoing and that conclusions about motive and affiliations have not been finalized. The university and local authorities have urged anyone with information to come forward as officials continue to piece together the events leading up to the shooting.

This is a developing story and will be updated as new information becomes available.

Charlie Kirk at an appearance