A senior Afghan minister has rejected accusations that he and other Afghan leaders were involved in human rights abuses.
Intimidation means girls are not going to school, says HRW
Education Minister Yunis Qanooni described the allegations as part of a plot organised by political circles inside and outside Afghanistan.
He said that he had always fought for human rights and spoken out against abusers.
In a report, Human Rights Watch said that abuses were carried out by soldiers and police and condoned by senior figures in President Hamid Karzai's government.
Warlords backed by the United States were creating a climate of fear in Afghanistan, it said, which could threaten next year's elections.
The report camesa day after a provincial governor called on US-led coalition forces to mount military operations to target resurgent Taleban forces.
Grip on power
Human Rights Watch's Brad Adams said the warlords had "hijacked" the country outside Kabul.
"Human rights abuses in Afghanistan are being committed by gunmen and warlords who were propelled into power by the United States and its coalition partners after the Taleban fell in 2001," he said.
"The United States and the United Kingdom in particular need to decide whether they are with President Karzai and other reformers in Kabul or with the warlords."
A spokesman for Mr Karzai said the government was doing all it could to cut down on human rights abuses but said it was "a gigantic task".
Among the police and army abuses described in the report are kidnappings, burglaries, rapes and extortions.
The group also says political activists and journalists are being harassed, arrested and threatened with death by security officials.
The abuses are being carried out by police working under senior officials, including cabinet ministers and provincial governors, the report claims.
In some parts of the country, the atmosphere of intimidation means that women are not leaving their homes and girls are not going to school.
The continued threat of Taleban forces is also causing concern in some areas.
Six Afghan policemen were killed in an ambush by suspected Taleban and al-Qaeda fighters in the Helmand Province on Sunday.
Fears of a Taleban resurgence led the deputy governor of the southern Zabol Province to call on the US-led coalition for military support.
Mullah Mohammed Omar, who shares his name with the ousted Taleban leader, said the province's own forces were unable to cope.
Hundreds of Taleban fighters were roaming freely in several districts, he said, intimidating government employees and supporters.
Last week about 1,000 Afghan National Army soldiers - a fifth of its total trained manpower - were deployed along with US and Italian troops in an operation aimed at tracking down the fighters.
Elections are due to be held in Afghanistan next year but the Human Rights Watch report warns that if the situation does not improve the democratic process will be under threat.