Kenya's largest newspaper printed shocking images Thursday of what appeared to be undercover police shooting three unarmed suspects at point-blank range on a busy Nairobi highway during midday, prompting a barrage of criticism.

Kenya's Minister for Internal Security George Saitoti confirmed three people were killed in the incident. He said three police officers are under investigation and could face charges.

The photos printed by the Daily Nation and taken by a passing motorist show two men lying face-down and an undercover police officer pointing a gun near them. A later photo shows two men with multiple bullet wounds to the head who appeared to be dead. A third killing also apparently took place.

The incident occurred on a well-traversed highway opposite a busy regional airport in Kenya's capital.

A minibus driver who said he witnessed the incident told The Associated Press he saw two police officers, one armed with a rifle and another with a pistol, order the three men out of a Toyota sedan. The officers then made the suspects lie on the ground.

"Suddenly there was gunfire everywhere, and the passengers in my vehicle were screaming," said the driver, who asked not to be identified for fear of retaliation. "Some were trying to jump through the window."

The British High Commission expressed "deep and serious concern" about the shootings, and said it regretted that Kenya has made little progress on impunity by government officials. A group called the Release Political Prisoners Trust said the shooting indicates that police death squads "are now completely out of control."

"It is now clear to all that the Kenya police have abandoned all pretext of any reform and are now operating totally outside the law," the group said.

The headline above the Daily Nation photos read "Executed point-blank" and an editorial inside the paper said Kenya's police must not become criminals themselves.

The paper reported that a police commander at the scene told journalists the suspects had drawn weapons on the police and fired at them, though the photos appear to show a far different tale. The driver who said he witnessed the incident told the AP he also did not see the suspects shoot at police.

"It was not an exchange of fire; nor by any stretch of the imagination could it pass as lawful use of lethal force," the Daily Nation's editorial read. "The victims posed absolutely no threat because they had clearly been subdued."

The paper also reported that after the killings, the police turned their guns on journalists at the scene and threatened to shoot them.

Saitoti said in a news conference Thursday that it is not government policy to execute suspects.

"We admit that there are rotten eggs and we are going to get rid of them," Saitoti said. "They are not the majority. We have good honest police officers out there."

But Hassan Omar Hassan, a commissioner with the government-funded Kenya National Commission on Human Rights, said the highway shootings support claims by rights groups that there is a silent government policy to use extrajudicial killings to combat crime.

"It's audacious. For you to have that kind of audacity to do it ... during morning traffic in broad daylight! It shows that it is a common practice or standard used by certain people in the police force, "Hassan said.

In a 2008 report, the commission said Kenyan police were to blame for the executions and disappearances of more than 500 people who were suspected of being members of a notorious gang. After the report's release, a police driver who told the commission he witnessed more than 50 executions by police was killed while in witness protection.

Philip Alston, then the U.N.'s expert on extrajudicial killings, investigated the deaths and disappearance of gang members and concluded in 2009 that Kenyan police were running death squads. A week after Alston's report, two rights activist who spoke to Alston were shot dead. Their car was raked with automatic gunfire on a leafy suburban street a minute's walk from the heavily guarded presidential residence.

Kenya is trying to implement wide-ranging government reforms. Saitoti said police reforms must continue to be implemented, including a civilian-controlled mechanism for investigating complaints against police.