Almost a decade before Psy became famous in the U.S. and all over the world for “Gangnam Style,” he allegedly rapped about “slowly and painfully” killing American soldiers and civilians, as reported by MTV News, which said he apologized Friday to anyone his words offended.

The worldwide sensation took to the stage in 2002 -- before practically anyone outside Korea had heard of him -- to protest against 32,000 American troops who were stationed on the Korean Peninsula. Psy held a miniature U.S. tank over his head and then smashed it on the ground to prompt a roar of applause from the crowd.

When a South Korean missionary was killed in Iraq two years later, Psy performed alongside other Korean artists at an anti-American protest concert. That’s when he rapped the song “Dear American,” whose lyrics mention killing U.S. soldiers and civilians:

“Kill those f---ing Yankees who have been torturing Iraqi captives.
"Kill those f---ing Yankees who ordered them to torture.
"Kill their daughters, mothers, daughters-in-law and fathers.
"Kill them all slowly and painfully.”

The song was originally done by N.EX.T, but Psy was said to have helped with the performance of the song at the 2004 concert.

The Korean lyrics and English translation were posted on CNN’s iReport a couple of months ago, and they were recently picked up by Mediaite and Twitchy.

Outrage directed at the Korean pop star has spread throughout the U.S. As a result, BuzzFeed reported, a petition is being posted on the White House’s “We The People” page asking U.S. President Barack Obama to rescind Psy’s invitation to the "Christmas in Washington" concert scheduled for the National Building Museum in Washington Sunday.

All the U.S. dollars he’s been raking in of late may have had something to do with Psy's apology Friday.