About 160 officers who were selected for separation from the Army can now remain on active duty or separate with retirement benefits, the service announced Thursday.

The decision to retain these officers was made by Army Secretary John McHugh.

The Army this year selected about 1,100 captains and more than 500 majors for involuntary separation as part of an ongoing drawdown to reach an end-strength of 490,000 soldiers by the end of fiscal 2015. Among those officers are soldiers who had previously served as enlisted troops but hadn't completed the minimum number of years of active commissioned service required before an officer is eligible for retirement.

As many as 44 prior-enlisted officers were improperly considered by the separation boards, and because they were selected, they would have been forced to retire at their highest enlisted rank.

Among the requirements for separating officers, the Army must consider both the soldier's active-duty service and active commissioned service, according to the Army's announcement Thursday.

However, in considering more than 19,000 potential candidates, the Army made its determination based only on active-duty service, not active commissioned service, meaning that one major and several captains were improperly considered for separation.

"Under the criteria for officer separations, these soldiers should not have been considered," McHugh said in a statement. "This is an issue of fundamental fairness, and today we have taken appropriate action."

The 44 officers in question were selected for early retirement even though they did not meet the minimum commissioned service threshold. McHugh voided their separations from service, and the officers have been notified that they may remain in the Army. They may still submit a voluntary request to retire at their previously held enlisted grade, or wait until they have the necessary years of active commissioned service required to retire as officers.

The other 120 or so officers affected by McHugh's decision were properly considered by the separation boards, but they would not have had the required years of active commissioned service needed to retire as officers upon their mandatory retirement date.

For years, a long-standing rule required prior-enlisted officers to serve at least 10 years of commissioned service before being eligible to retire as officers. In a June 17 directive, McHugh reduced that minimum to eight years, the shortest amount of time allowed under federal law.

Now, McHugh, exercising his legal authority, has suspended the eight-year requirement for active commissioned service, allowing all who are retirement eligible to retire as officers.

"These soldiers have served their country honorably both as enlisted soldiers and, now, as officers," McHugh said. "We owe them nothing less."

The Army was alerted to the issue via a Congressional inquiry, the service said.

"We appreciate that this oversight was brought to our attention, and glad we were able to take corrective action in the best interests of these soldiers," McHugh said.

A group of 15 senators wrote to McHugh about this issue in November.

The lawmakers, led by Sen. Patty Murray of Washington and Sen. Johnny Isakson of Georgia, said they have "grave concerns" over the treatment of these officers and called on the Army to change its policy to "delay the mandatory retirement date of affected soldiers until the first month after they become eligible to retire as commissioned officers."

Forcing the officers to retire at their highest enlisted rank could cause them to lose as much as $1,000 a month in some cases, the senators wrote. That could mean a "significant decrease" in retirement pay worth just over $1 million over a 40-year retirement in the case of a captain who's forced to retire as a sergeant first class, according to the senators' letter.

"These former non-commissioned officers answered the Army's call for volunteers to attend Officer Candidate School as the Army expanded its officer corps to fight the wars in Iraq and Afghanistan. Now, despite having served for years as commissioned officers and rising through the ranks to become captains and majors, these dedicated soldiers will soon be forced to retire at their highest previous enlisted rank," the letter states. "To demote these soldiers in retirement is an injustice that devalues their service and will materially disadvantage them and their families for the rest of their lives."

In a statement Thursday, Isakson applauded the Army's quick response.

"I am thrilled Secretary McHugh responded quickly and is taking the steps necessary to rectify this situation and allow these deserving men and women to retire at the rank they have earned and appropriately honor their service to our nation," he said.