He also warned that the federal government was "taking a stand" against the "culture of leaking" and took a moment during his prepared remarks to speak directly to "would-be leakers."
"Don't do it," said Sessions.
"Referrals for investigations of classified leaks to the Department of Justice from our intelligence agencies have exploded," said Sessions.
The attorney general said that in response to the increase, the FBI has boosted resources devoted to leak cases and created a new "counterintelligence unit to" manage the cases.
"There’s a new unit within the FBI that’s focused on media leaks and the reason for that is that there are unique issues," Deputy Attorney General Rod Rosenstein said after the announcement.
"We recognize that there’s some similarities to espionage and unauthorized disclosure cases, but there are unique challenges for the leak cases, so we think it’s important to have dedicated unit of agents and a supervisor,” he added.
Rosenstein, along with newly-sworn-in FBI Director Christopher Wray, have been tasked with overseeing all leak investigations and "actively monitoring" each case.
In addition, Sessions directed the National Security Division and U.S. attorneys across the country to "prioritize" cases of unauthorized disclosures.
Sessions referenced journalists as he detailed Friday the input he received on how best to combat the issue.
"I've listened to our career investigators, FBI agents and others, and of prosecutors about how to most successfully investigate and prosecute these matters," said Sessions. "At their suggestion, one of the things we are doing is reviewing policies for effecting media subpoenas."
Current Justice Department policy on the topic, as described in the Code of Federal Regulations, states that the use of subpoenas, and other "law enforcement tools" to obtain information from members of the news media, are viewed as "extraordinary measures, not standard investigatory practice."
The section notes that the subpoenas will only be authorized "when the information sought is essential ... after all reasonable alternative attempts have been made to obtain the information from alternative sources." The policy makes an exception for instances in which the media member is the "target" of the investigation or when "conduct" occurred outside of "newsgathering activities."
Obama-era Attorney General Eric Holder had established a standard during his tenure that "as long as I am attorney general, no reporter is going to go to jail for doing their job.” That standard was adhered to by his successor Loretta Lynch.
“We don’t know yet [of any] changes we are making, but we are taking a fresh look at it," said Rosenstein about the process of conducting media leak investigations.
Journalism organizations and others expressed concern over the potential changes.
"We don’t know where this is going, but I think there are reasons to be concerned that the changes would weaken the protections for journalists that are essential to the public interest," Bruce D. Brown, the executive director for the Reporters Committee for Freedom of the Press, said.
The Reporters Committee was deeply involved in revising the DOJ guidelines in 2015, which was agreed to by the DOJ, career prosecutors, the intelligence community and the FBI at the time, said Brown.
"It was dismaying today to hear that the AG was going to revisit" the policy, he added.
Rosenstein said the DOJ is in the process process of initiating its review and anticipated that the department will consult with media representatives this time as well.
The New York Press Club called Sessions' remarks about a Justice Department crackdown on information leaks to the media "a not-so-veiled shot across the bow at the news media."
"Journalists will not be intimidated by the attorney general's threats," the press club said in a statement.
In June, U.S. intelligence agencies formally asked the Department of Justice to investigate Russia-related “leaks,” according to sources familiar with the matter at the time.
The relationship between Trump and Sessions has been strained for weeks, partly due to the attorney general's decision in March to recuse himself from matters related to last year's election. Today's announcement comes 10 days after the president was asked at a news conference whether or not he was going to fire Sessions.
Though the announcement on leaks had been first discussed weeks ago, it comes on the heels of The Washington Post story detailing transcripts of calls that Trump had with Mexican President Enrique Pena Nieto and Australian Prime Minister Malcolm Turnbull earlier this year.
"No one is entitled to surreptitiously fight to advance battles in the media by revealing sensitive government information," said Sessions after referencing the call logs released Thursday. "No government can be effective when its leaders discuss sensitive matters and confidence or talk freely and confidence with foreign leaders."
"Can you imagine being president of the United States, having a conversation with a foreign leader and that conversation being divulged to the media," Graham said. "It's just not fair to President Trump."
ABC News' Mike Levine, Chris Donovan, Mary Bruce and Ali Dukakis contributed reporting to this story.