Former Blackwater security guard Evan Libebty. (AP file photo)

One of the four Blackwater security contractors, pardoned by US President Donald Trump in a controversial move last month, says he acted correctly in a 2007 massacre of Iraqi civilians in Baghdad.

Evan Shawn Liberty had been convicted along with three other Blackwater guards for a shooting rampage that killed 14 civilians in Baghdad, but they were pardoned by the US president in a move which shocked everyone, including Americans.

In his first interview since his release, Liberty showed no sign of remorse, saying instead he felt like he acted correctly.

I regret any innocent loss of life, but I’m just confident in how I acted and I can basically feel peace with that, he told the Associated Press.

Liberty and the three other guards had been convicted for their role in the massacre, in a US court in 2015, after seven years.

Th court had found one of them, Nicholas Slatten, guilty of first-degree murder, while Paul Slough, Dustin Heard and Liberty had been convicted of voluntary and attempted manslaughter.

After an appeal, they were each given between 12 and 15 years in prison.

They have already defended themselves, saying that they acted in self-defense.

An FBI agent, who led the investigation into the Baghdad incident, denounced the pardon in a letter to New York Times published Saturday, saying that he was embarrassed for our country.

I believe we will pay a heavy price in our relationships with other countries as a result of these pardons, he wrote.

Patarini wrote that he led the investigation into Baghdad’s Nisour Square massacre, initially thinking the shooting was some form of innocent civilians caught in the crossfire between the Blackwater guards and militants at the time.

After only one week, however, he discovered that the incident was not as what Blackwater, now renamed Academi, and State Department officials had described.

It was actually a carnage similar to the My Lai massacre where between 347 and 504 unarmed civilians were killed by US Army soldiers during the Vietnam War, he wrote.

Trump’s order which came in the waning days of his administration sparked anger among human rights groups and the United Nations, who described the move as a violation of US obligations under international law.

Presidential pardons have historically been reserved for nonviolent crimes, but Trump has recently used his power in pardoning his allies, who were charged in high-profile cases.