The cockpit recording, which was obtained by Britain's The Sun newspaper, reportedly captures the voices of two American A-10 pilots before and after they mistakenly opened fire on a British military convoy near Basra, Iraq, on March 28, 2003.
One of the pilots is heard cursing.
"We're in jail, dude," another responds.
• VIDEO: Click Here to Watch The Sun's Exclusive Footage
The incident occurred just seven days into the war as two pilots were nearing the end of a two-hour mission to destroy rocket launchers and artillery from former Iraqi dictator Saddam Hussein's 6th Armored Division. The pilots were flying "tankbusters," jets whose prime mission is to destroy tanks.
The enemy rocket launchers were dug into positions 25 miles north of Basra. Meanwhile, a British convoy of four armored vehicles was making its way north to probe enemy defenses.
Circling at 12,000 feet, one of the pilots spotted the Iraqi vehicles 800 yards north of the target of their previous attack run, as well as the convoy about three miles away. A Marine Forward Air Command official, code-named "Manila Hotel," asks them to engage the targets.
The pilot, identified by the call sign POPOV36, radioed back that the vehicles' roofs appeared to display orange painted panels used to indicate coalition forces to aircraft. The pilot asked Air Command to confirm that there were no "friendlies this far north on the ground."
"That is an affirm," Manila Hotel radioed back. "You are well clear of friendlies."
POPOV36 then contacted the second A-10 pilot, codenamed POPOV35, to coordinate the attack on the vehicles with "orange rockets" attached to them. An apparently confused POPOV35, however, requested that Forward Command fire an artillery round at the target to clear up the confusion, then suggested that the pair should return to base due to time constraints.
"I think killing these damn rocket launchers, it would be great," POPOV36 replied before rushing in to strafe the convoy.
Seconds after the circling for a second attack, American and British voices frantically call the A-10s to call off the attack — but the damage already had been done. Lance Cpl. of Horse Matty Hull, 25, died of injuries sustained as the A-10s pumped 50 rounds per second of armor-piercing shells into the convoy. Four other British troops also were injured.
"I'm going to be sick," POPOV35 radioed when Air Command broke the news. POPOV36 can be heard sobbing in the background.
A British investigation into the 25-year-old's death was adjourned last week after a coroner said he "had no choice" but to delay his verdict because the United States refused to release the tape.
"A copy of the video was used as evidence by the Board of Inquiry's investigation into the incident. ... This recording is the property of the United States government and the [Ministry of Defense] does not have the right to release it without their permission," a U.K. Defense spokeswoman said.
The incident has been a sore spot with some British lawmakers who have demanded that U.S. soldiers involved in friendly fire incidents attend U.K. hearings. The United States has denied requests for servicemen to appear in court but does submit anonymous statements on each case.
Hull's widow, Susan Hull, said she was told the tape can help bring justice for her husband, the Sun reported.
"I'm very relieved this is being made public at long last," she said. "I can't believe these pilots can discuss what they're doing so casually when these are the last moments of my husband's life."
Sources last week said the tape, which the Ministry of Defense claimed did not exist, was "incriminating."
A senior U.S. military source told The Sun: "This tape needs to get out. The pilots need to be brought to account."
The Sun is owned by News Corp., which is the parent company of FOXNews.com.