Two innocent teenagers carrying a cricket bag were beaten to death by a mob in Pakistan who mistook them for thieves.

Their deaths, watched by police who did nothing to intervene, were captured on video footage that has outraged the country.

It shows men taking turns savagely beating the two brothers with sticks, drawing blood before dragging and hanging their bodies from a nearby pole.

None of the dozens of people watching tried to stop the attack.

The incident is a blow to the already-shoddy image of the government as it appeals for international aid to cope with disastrous floods.

"Is this what we are? Savages?" asked an editorial in The News, an English-language daily. "So utterly bereft of a speck of humanity that a crowd of ordinary men are passive spectators to public murder?"

The killings happened on August 15 in Sialkot, a town in eastern Punjab province. As details emerged, authorities appear increasingly confident the two boys - Moiz Butt, 17, and his brother Muneeb, 15 - were innocent.

The two went to play cricket after praying and eating breakfast, carrying a bag with them containing game equipment, said Mujahid Sherdil, a top government official in the district. They were sons of a middle-class man who deals in fabric for soccer balls. Moiz was honoured with the title "hafiz" for having memorised the Koran.

An armed robbery had taken place near the cricket field, so residents were on alert and police were nearby. Apparently, when the boys appeared with a bag, they were thought to be the robbers, Sherdil said.

He added, however, that more information was still being sought. The boys were believed to have been in fights over the past few days for the right to play on the cricket ground, which was about a mile from their house.

The origins of the video are unknown and there are reports that multiple men in the crowd recorded the attack using phones. Stations blurred out some of the more graphic images of the boys' bloodied bodies, but several faces in the crowd are clearly identifiable, including police officers in uniform who watched.

Punjab province Police Chief Tariq Saleem said the government has ordered two separate inquiries into the killings.

"This incident is highly condemnable, especially in the police presence," Saleem said after visiting the boys' family. "All accused, including police, will be arrested soon."

It is unclear whether such mob killings are more common now in Pakistan, but they are more likely to get reported and affect the public consciousness because of the explosion of electronic media during the last decade.

Over the past two years, police and even soldiers have been caught on video beating suspects. In 2008, in two separate incidents in less than a week, crowds set fire to suspected robbers in the southern city of Karachi. In the first incident, a picture of men lying like logs in a fire made front pages.

Civic groups condemned the attack in Sialkot, and the media attention forced the government to respond. But many suspects never get caught - one reason mobs feel free to go after victims on their own.

Federal Interior Minister Rehman Malik visited the family of the two boys Sunday in Sialkot and issued an appeal for citizens to come forward with evidence to help the investigation. He said at least 10 suspects have been arrested, including four police officers.

Malik said the police should have at least fired their guns in the air to disperse the crowd, and added people should not take the law into their own hands.

"It is not the kind of incident any civilised society can afford," he said. "The whole of Pakistan wants the people involved to be punished. And we are getting demands from the nation that they should be hanged at the very place where they murdered the two brothers."

The brothers' killings came as Pakistan's government is reeling from other crises, including the worst flooding in decades. The calamity appears to have further eroded confidence in the government, a key Western ally in the fight against Islamist extremism.