Chelsea Manning, the former soldier whose sentence President Barack Obama commuted this week, placed the lives of at least 900 Afghans aiding U.S. troops at risk by orchestrating the biggest leak in American military history.

Manning will be leaving prison in May, having served seven of the 35 years he was sentenced to spend in prison.

In July 2013, retired Army Brig. Gen. Robert A. Carr, a former counterintelligence official, revealed that a Pentagon task force found nearly 900 names of local Afghan nationals contained in the Manning’s leaked records. Manning shared 700,000 classified documents and video with WikiLeaks, which published them without redacting names.

Carr led the Pentagon’s review of the fallout from the WikiLeaks disclosures.

According to Obama administration defense officials, American lawmakers, and former Afghan President Hamid Karzai, the former soldier endangered the lives of U.S. military informants and American troops by leaking classified U.S. military information to WikiLeaks.

“We consider that extremely irresponsible and an act that one cannot overlook,” Karzai said at the time, accusing WikiLeaks of placing the lives of Afghans in danger by disclosing the documents it obtained from Manning.

“In some cases, lives will be harmed,” declared retired Gen. Carr while serving as the U.S. government’s first witness in the sentencing phase of Manning’s court-martial in July 2013.

Echoing Carr, Rear Adm. Kevin Donegan, former operations director of U.S. Central Command (2010-2012), which covers American military operations in Iraq and Afghanistan, testified that Manning has ” endangered Afghan villages that might be perceived as friendly toward U.S. or coalition forces.”

Donegan, the U.S. Army prosecutor’s last witness in August 2013, went on to say that “there was absolutely an impact” on the U.S. government from the leaked information.

In the wake of the leaks, Manning forced the Pentagon to set up a warning system for any Afghan or Iraqi national whose co-operation with the U.S. military may have put their life in danger.

According to The New York Times (NYT), WikiLeaks founder Julian Assange refused to redact the names of Afghan informants mentioned in the documents leaked to the public in 2010, telling the Guardian, “If an Afghan civilian helps coalition forces, he deserves to die.”

NYT noted that, eventually, “computer-savvy volunteers at the [WikiLeaks] organization corrected Mr. Assange’s mistake and used an inventive computer program to scrub names and identities from the second leak of documents, the Iraq War Logs.”

In July 2010, retired Adm. Mike Mullen, then-chairman of the U.S. Joint Chiefs of Staff, told reporters that Assange may have “blood” on his hands “of some young soldier or that of an Afghan family” after leaking the documents provided by Manning who is currently known as Chelsea.

Although, at of the time of Manning’s sentencing, there was no evidence linking the released classified information to any fatalities, those named in the Manning documents face indefinite targeting by jihadist groups for having cooperated with American soldiers.

Manning was found guilty of 20 counts affiliated with leaking classified information linked to the wars in Iraq and Afghanistan, including six counts under the Espionage Act, but was ultimately acquitted of the most serious charge of “aiding the enemy,” which carries a sentence of life behind bars without the possibility of parole.

The former soldier’s disclosure is considered to be unprecedented.

Carr pointed out that the leak has damaged the relationship between the U.S. Army and the Afghan people. He also said that U.S. supply lines have been compromised because Manning divulged details of military logistics.

Former Rep. Howard “Buck” McKeon (R-CA), then-chairman of the House Armed Services Committee, welcomed the 35-year sentence imposed on Manning. “Bradley Manning endangered the security of the United States and the lives of his own comrades in uniform when he intentionally disclosed vast amounts of classified data,” he said.

President Obama’s decision to commute the sentence of the convicted leaker has drawn sharp rebuke from GOP leaders in Congress.

“This is just outrageous. Chelsea Manning’s treachery put American lives at risk and exposed some of our nation’s most sensitive secrets,” said House Speaker Paul Ryan (R-WI). “President Obama now leaves in place a dangerous precedent that those who compromise our national security won’t be held accountable for their crimes.”

“I’m stunned,” Sen. John McCain (R-AZ), chairman of the Senate Armed Services Committee, added. “President Obama’s commutation of Chelsea Manning’s sentence is a grave mistake that I fear will encourage further acts of espionage and undermine military discipline. It also devalues the courage of real whistleblowers who have used proper channels to hold our government accountable.”