The U.S. army made critical errors while in handling the friendly fire death of an American soldier in Afghanistan, but there was no criminal wrongdoing, the military concluded Monday.

The military was investigating the death of army Ranger Pat Tillman, 27, an NFL star who walked away from a $3.6-million US football contract in 2001 to enlist. Tillman was killed April 22, 2004, in a gun battle with enemy fighters near the Afghanistan-Pakistan border.

The military initially told the public and Tillman's family that Tillman had been killed in an ambush, but did not say the fatal wound was caused by members of his own unit.

Several weeks later, the army admitted Tillman was accidentally killed by fellow U.S. soldiers in rough terrain when the lighting was poor.

Investigators with the U.S. army and Defence Department concluded Monday that high-ranking officers who were looking into the incident at the time passed along misleading and inaccurate information. The officers also delayed reporting their belief that Tillman had been killed by friendly fire, said investigators, who released their findings in two reports.

General found at fault

Among the officers blamed is Lt.-Gen. Stanley McChrystal, a three-star general who was in charge of the army's special operations, the investigators said.

They recommended that the army take action against the officers. Army officials said Monday they would.

"We as an army failed in our duty to the Tillman family, the duty we owe to all the families of our fallen soldiers: give them the truth, the best we know it, as fast as we can," said acting army secretary Pete Geren.

"Our failure in fulfilling this duty brought discredit to the army and compounded the grief suffered by the Tillman family. For that, on behalf of the army, I apologize to the Tillman family."

Still, the military concluded Monday that the army and its officers were not attempting a coverup in Tillman's death.

"We thought there was never an attempt to cover up that we saw," Insp. Gen. Thomas Gimble of the Defence Department said.

Decision under review

Investigators recommended the army review its decision to award Tillman the Silver Star, one of the army's highest honours. Tillman received the award posthumously in 2004.

Some of the information used to justify honouring Tillman with the award was inaccurate and misleading, Gimble said. Officers, including McChrystal, provided that information, he said.

The army said it won't take the Silver Star from Tillman, but it will rewrite the citation to correct all inaccuracies.

Tillman, who grew up in San Jose, Calif., was a safety with the NFL's Arizona Cardinals. He was offered a three-year extension to his contract but turned it down to join the army shortly after the Sept. 11, 2001, attacks on the United States. The Cardinals have retired Tillman's No. 40 uniform.