BAGHDAD - Four former Blackwater guards found guilty for their role in the 2007 massacre of at least 14 civilians in Baghdad’s busy Nisur Square should be executed, relatives of victims said Thursday.

Their convictions followed a two-month trial that heard how they opened fire with sniper rifles, machine guns and grenade launchers in Baghdad’s bustling Nisur Square as they escorted a diplomatic convoy.

The shooting exacerbated Iraqi resentment toward Americans and exemplified the impunity enjoyed by private security firms on the US payroll in Iraq.

“They should be executed in the same place in Nisur Square where they committed the crime,” said Hussein Ali Abbas, the brother of one of the victims.

His brother Saadi was on the way to visit a friend when the shooting occurred, and tried to flee but was gunned down anyway, Abbas said. “The conviction is not enough,” he said. “Justice was not achieved.”

Khaled Walid, whose father was among those killed, agreed: “Everyone said they should be sentenced to death.” “I demand the harshest sentence,” said Saddam Jawad, whose mother was killed. “If there is the death penalty in America, we demand the death penalty.” But the death penalty is not on the table for any of them.

One guard, Nicholas Slatten, was convicted of first-degree murder, which carries a potential life sentence. The others were found guilty of voluntary manslaughter and will be jailed for at least 15 years for each killing.

Before the incident, Slatten allegedly told acquaintances he wanted to “kill as many Iraqis as he could as ‘payback for 9/11,’” court documents showed.

Hassan Jabr Salman, who was wounded in the shooting, welcomed the convictions after the long delay. “Thanks be to God... Justice was achieved at last,” he said.

While the conviction does not go as far as he would like, it is still “a victory for the martyrs and the wounded.”

Iraqi officials say 17 civilians were killed, while US investigators recorded 14 deaths. A further 18 Iraqis were wounded.

In the aftermath of the killings, Blackwater was forced to cease operating in the country.

But a US diplomatic cable released by whistleblower website WikiLeaks said hundreds of former Blackwater guards kept working in Iraq for other companies.

Blackwater later renamed itself Xe Services and then Academi in an effort to shed the infamy it gained in Iraq.