Lawyers for four former Blackwater security guards convicted Wednesday in the 2007 shootings of more than 30 Iraqis in Baghdad plan to appeal, they said. The convictions stemmed from an incident that inflamed anti-American sentiment around the globe and was denounced by critics as an illustration of a war gone horribly wrong.

The men claimed self-defence, but federal prosecutors in Washington argued that they had shown "a grave indifference" to the carnage their actions would cause. All four were ordered immediately to jail Wednesday.

Their lawyers promised to file appeals. The judge did not immediately set a sentencing date.

The federal jury found Nicholas Slatten guilty of first-degree murder, the most serious charge in a multi-count indictment. The three other guards — Paul Slough, Evan Liberty and Dustin Heard — were found guilty of multiple counts of voluntary manslaughter, attempted manslaughter and gun violations.

The outcome after a summer-long trial and weeks of jury deliberation appeared to stun the defence.

David Schertler, a lawyer for Heard, said, "The verdict is wrong, it's incomprehensible. We're devastated. We're going to fight it every step of the way. We still think we're going to win."

However, one of those struck by gunfire in the shootings, Hassan Jabir, said in Baghdad that "at last we are hearing good news where justice has been achieved and Blackwater will receive their punishment." He said there are two bullets still inside his body, one in his hand and one in his back, which doctors have said it would be very risky to remove.

The shootings on Sept. 16, 2007, caused an international uproar over the role of defence contractors in urban warfare.

The State Department had hired Blackwater to protect American diplomats in Baghdad, the Iraqi capital, and elsewhere in the country. Blackwater convoys of four heavily armoured vehicles operated in risky environments where car bombs and attacks by insurgents were common.

All 4 face decades behind bars

On the murder charge, Slatten could face a maximum penalty of life in prison. The other three defendants could face decades behind bars.

The case was mired in legal battles for years, making it uncertain whether the defendants would ever be tried.

The trial itself focused on the killings of 14 Iraqis and the wounding of 17 others. During an 11-week trial, prosecutors summoned 72 witnesses, including Iraqi victims, their families and former colleagues of the defendant Blackwater guards.

There was sharp disagreement over the facts in the case.

The defendants' lawyers said there was strong evidence the guards were targeted with gunfire from insurgents and Iraqi police, leading the guards to shoot back in self-defence. Federal prosecutors said there was no incoming gunfire and that the shootings by the guards were unprovoked.

The prosecution contended that some of the Blackwater guards harboured a low regard and deep hostility toward Iraqi civilians.

The guards, the prosecution said, held "a grave indifference" to the death and injury that their actions probably would cause Iraqis. Several former Blackwater guards testified that they had been generally distrustful of Iraqis, based on experience the guards said they had had in being led into ambushes.

The four men had been charged with a combined 32 counts in the shootings and the jury was able to reach a verdict on all of them, with the exception of three against Heard. The prosecution agreed to drop those charges.

Slough was convicted of 13 counts of voluntary manslaughter and 17 counts of attempted manslaughter. Liberty was convicted of eight counts of voluntary manslaughter and 12 counts of attempted manslaughter. Heard was convicted of six counts of voluntary manslaughter and 11 counts of attempted manslaughter.

Voluntary manslaughter carries a penalty of up to 15 years in prison and attempted manslaughter carries a maximum seven years in prison.

All three were also convicted on gun charges that carry a mandatory minimum sentence of 30 years in prison.

Prosecutors said that from a vantage point inside his convoy's command vehicle, Slatten aimed his SR-25 sniper rifle through a gun portal, killing the driver of a stopped white Kia sedan, Ahmed Haithem Ahmed Al Rubia'y.

At the trial, two Iraqi traffic officers and one of the shooting victims testified the car was stopped at the time the shots were fired. The assertion that the car was stopped supported the prosecution argument that the shots were unwarranted.

Defense lawyers pressed their argument that other Blackwater guards — not Slatten — fired the first shots at the Kia sedan and that they did so only after the vehicle moved slowly toward the convoy, posing what appeared to be a threat to the Blackwater guards' safety.

Once the shooting started, hundreds of Iraqi citizens ran for their lives.

It was "gunfire coming from the left, gunfire coming from the right," prosecutor Anthony Asuncion told the jury in closing arguments.

One of the government witnesses in the case, Blackwater guard Jeremy Ridgeway, had pleaded guilty to killing the driver's mother, who died in the passenger seat of the white Kia next to her son.

After Wednesday's verdict, Liberty's attorney William Coffield said he expected to appeal.

Among the grounds for doing so would be an issue involving the law under which the defendants were charged, the Military Extraterritorial Jurisdiction Act. Defence lawyers say that law should not apply because the guards were contractors for the State Department, not the Pentagon.