"Creating friction with a key ally with an issue like that may have been a mistake, frankly", he told AFP.
Added Trump: "So, I think the rhetoric, I hated to do it".
"It's important for us to remember that it's largely words at this point, and that we have to look for actions, particularly from North Korea", Panetta said during an interview with FOX Business' Neil Cavuto on Tuesday.
MSNBC's special coverage of the Trump-Kim summit finished second in total viewers with 2.378 million.
"A lot of people, critics quickly saying when you said "Little Rocket Man" or 'fire and fury, ' or when he said, 'Oh, I've got a red button on my desk, ' and you said, 'Well, mine's bigger and it works better than yours, ' how did it evolve from that to this?"
South Korean President Moon Jae-in spoke by phone with Trump for 20 minutes late on Tuesday, but an official readout of the call made no mention of military exercises.
U.S. President Donald Trump's declaration on Tuesday that he meant to end joint military exercises in Korea seemed to be news to both South Korean and U.S. military officials.
"There were no surprises", she said.
USA officials and the North Korean state news agency struck a hopeful tone as the meeting approached, while negotiators from both countries met privately in the last hours to iron out agreements, such as over the definition of denuclearisation and the terms under which Pyongyang might agree to dismantle its nuclear arsenal. Drills called Team Spirit, one of the largest annual military maneuvers in the world at the time, were held from 1976 until 1993, when, after North Korea agreed to dismantle its existing nuclear facilities, the exercises were canceled and have not been held since.
Trump also seemed annoyed that US bomber aircraft make six-plus hour flights from the Pacific island of Guam to the Korean peninsula as part of its exercise routine.
Exercises with South Korea cover a range of eventualities, including drills with nuclear-capable bombers.
Hannity, who sat down with Trump for an interview after the summit, even compared Tuesday's event to former President Ronald Reagan's meeting with Soviet leader Mikhail Gorbachev at the height of the Cold War.
Dennis Rodman Breaks Down In Tears Discussing Trump-Kim Summit
The former athlete went on to say that Un is "more like a big kid - even though he's small - who loves to have a good time". Cuomo appeared sullen and, at times, startled as Rodman turned tearful. "This is all such a sh*t show", one user tweeted .
India Welcomes Donald Trump-Kim Jong Un Summit
The much-anticipated summit marked the first ever meeting between a top DPRK leader and a sitting USA president. Kim and Trump signed the "historic" document after their Singapore meeting.
Armed man takes three hostage in Paris
The Paris prosecutor's office detained the suspect, a 26-year-old man born in Morocco, a judicial official said. He reportedly struck one man, who managed to escape, but was doused with gasoline .
Actress Rose McGowan indicted on cocaine charge in Virginia
When the narcotics accusations against McGowan surfaced, she said it was an attempt to silence her and was a "load of horsesh*t". Rose has pleaded not guilty to the case, and states that she was without the wallet for five hours before she retrieved it.
North Korea sanctions to 'remain in effect’
He said it was a last minute deal and expected more than 6,000 Americans' remains to be brought back to the U.S. If we've learned anything during President Trump's time in the Oval Office, it's that he loves Twitter .
Belmont Stakes 2018 FREE LIVESTREAM
Justify crosses the finish line and wins the Triple Crown at the 150th Belmont Stakes, in Elmont, N.Y., on Saturday, June 9, 2018. Justify will attempt to join previous Triple Crown winners later this evening when he runs in the 2018 Belmont Stakes .