South Bend, Indiana Mayor Pete Buttigieg, who launched a an exploratory committee in January to run for president in 2020 as a progressive Democrat, is criticizing former Army intelligence analyst Chelsea Manning and former NSA contractor Edward Snowden for disclosing classified information.

Buttigieg left his day job as mayor to serve as a lieutenant in the Navy Reserve in Afghanistan in 2014, before returning to office. He said while deployed he was expected to read intelligence briefs before going on patrol and is criticizing Manning and Snowden, saying they abused their access to classified information.

Buttigieg told CBS News Radio on the sidelines of the South by Southwest Festival where he spoke over the weekend that he was "troubled" by former President Obama's decision to commute the 35-year prison sentence for Chelsea Manning days before he left office in 2017.

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Manning was convicted of disclosing classified government and military documents to Wikileaks. Manning was arrested in 2010 as Bradley Manning, before announcing she was transgender.

Manning was ordered to return to jail last Friday after refusing to testify to a grand jury investigating Wikileaks.

Buttigieg also took aim at Snowden's leaks, but didn't say whether he thought Snowden should be returned to the U.S. from Russia, where he is avoiding prosecution. Buttigieg called this an "international diplomatic challenge."

"I certainly agree that we've learned things about abuses and that one way or another that needed to come out," Buttigieg said. "But in my view, the way for that to come out is through Congressional oversight, not through a breach of classified information."

The 37-year-old Harvard graduate and Rhodes scholar, who married his boyfriend Chasten Glezman last June, also blasted a federal judge's ruling last week allowing the Trump administration to continue restrictions on transgender troops.

"Anybody who is competent to serve this country, and wants to do so and is willing to put their life on the line should have nothing but the support of their president, of their government," he said.

Buttigieg has also been speaking out against the former governor of his home state Vice President Mike Pence for what he calls a "social extremist ideology" attacking gay rights.

"I don't think he could possibly be a good president, and I don't think he's benefited our nation as Vice President either," Buttigieg said.

Buttigieg supports Supreme Court reform, comprehensive against climate change, and universal health care. But recent polls show support for Buttigieg among Democratic voters at less than one percent.