President Obama said he first learned from news reports that Hillary Rodham Clinton used a private email account while serving as his secretary of State.
"The policy of my administration is to encourage transparency, which is why my emails, the BlackBerry I carry around, all those records are available and archived," Obama said in excerpts of an interview with CBS News that aired Sunday. "I'm glad that Hillary's instructed that those emails about official business need to be disclosed."
Obama's first comments on the controversy came as a leading Democrat, Sen. Dianne Feinstein of California, said Clinton should speak publicly about her emails or risk damaging her potential 2016 presidential campaign.
"She is the leading candidate, whether it be Republican or Democrat, to be the next president, and I think she needs to step up and come out and state exactly what the situation is," Feinstein said on NBC's "Meet the Press." "I think from this point on the … silence is going to hurt her."
Clinton's only comment came on Twitter last week: "I want the public to see my email. I asked State to release them. They said they will review them for release as soon as possible."
The State Department is reviewing 55,000 pages of her emails to determine whether they can be released to the public.
Feinstein added that the regulations on personal email use were unclear during Clinton's tenure as secretary of State, from 2009 to 2013.
Colin L. Powell, who served as secretary of State from 2001 to 2005 under President George W. Bush, told ABC's "This Week with George Stephanopoulos" that he didn't retain any of the work emails he sent from a personal account during his tenure.
A federal law enacted in November requires the preservation of work emails from private accounts of government officials.
The Clinton controversy dominated discussion on Sunday TV talk shows, with Democrats, including Feinstein, defending her use of private email as legal.
The New York Times reported last week that Clinton used a private email account for her work messages. Then the Associated Press reported that Clinton had exclusive control over her email through a private server linked to her New York home.
A key Republican on Sunday reiterated his concern that Clinton had not turned over all relevant emails regarding her role in the U.S. response to the fatal 2012 attack on U.S. facilities in Benghazi, Libya.
The State Department has turned over some emails to the House select committee investigating the Benghazi attack, which left four Americans dead, including the ambassador. But the panel's chairman, Rep. Trey Gowdy (R-S.C.), said on CBS' "Face the Nation" that "there are gaps of months and months and months" between emails.
There were no emails from a trip Clinton made to Libya in October 2011, in which she was photographed en route in sunglasses looking at her handheld device — a picture that has been published in recent days with articles about the controversy, Gowdy said.
"It strains credibility to believe that if you're on your way to Libya to discuss Libyan policy that there's not a single document that's been turned over to Congress," he said.
Gowdy's committee said last week that it had subpoenaed Clinton's personal emails related to the attack.