WASHINGTON (Reuters) – The Pentagon said on Thursday that it found no threat in its review of about 850 military students from Saudi Arabia studying in the United States, following a Dec. 6 shooting by a Saudi Air Force officer who killed three people at a base in Florida.

“We can report that no information indicating an immediate threat scenario was discovered,” said Garry Reid, a director for defense intelligence, counter-intelligence, law enforcement and security, briefing Pentagon reporters. The conclusion clears the way for the U.S. military services to, at their discretion, lift a freeze on operational training that had grounded Saudi military pilots and had restricted Saudi air crews to infantry officers to classwork.

The FBI has said U.S. investigators believe Saudi Air Force Second Lieutenant Mohammed Saeed Alshamrani, 21, acted alone at a U.S. Navy base in Pensacola before he was fatally shot by a deputy sheriff.

A group that tracks online extremism has said Alshamrani appeared to have posted criticism of U.S. wars in predominantly Muslim countries and quoted slain al Qaeda leader Osama bin Laden on Twitter hours before the shooting.

The Pentagon said it would carry out the enhanced review of international military students for other nationalities as well, including looking at their social media. There are roughly 5,000 from 150 countries training on U.S. bases.

A U.S. defense official, speaking on the condition of anonymity, said the review did not speak to any information that the FBI may be gathering separately about the shooting.

So far, apart from the shooter who killed three people, the FBI investigation has not uncovered evidence that other potentially violent militants are embedded amongst Saudi military personnel now training in the United States, law enforcement officials said.

A FBI official told Reuters that the Bureau's Joint Terrorism Task Force and Counterterrorism division were “working tirelessly to discern if any possible ideology may have been a factor” in the Pensacola shooting, and also looking into “whether he acted alone or was part of a larger network.”

But the official said that so far investigators had not “identified a credible risk to the community as a result of this investigation.” The official added that the FBI had conducted over 500 interviews with help from other government agencies.