As the Afghan government struggles to stem the Taliban insurgency and shore up its dwindling security forces, the US military is turning to a controversial solution long known to stoke unrest and exploitation: local militias.

International donors, including the UN, have warned against such plans and lobbied the Afghan president to reject the US proposal. They say the new militias resemble the Afghan Local Police, a force notorious for grave human rights abuses and destabilising villages by undermining the central government.

The so-called Afghan National Army Territorial Force, essentially self-defence units of locally recruited men serving in their own villages, will be piloted with 1,000 men, once the Afghan president, Ashraf Ghani, approves the proposal, and will eventually number some 20,000, officials say.

Its aim, according to a Nato proposal circulated among embassies, will be to stabilise areas cleared by regular security forces and establish law and order.

Yet some worry that the force will amplify existing rivalries and be difficult to regulate. The national army, which will oversee the new force, is already fraught with poor leadership.

“When you pour resources into a community, everybody fights for them. Every tribal leader wants to have his share,” said Borhan Osman, from the International Crisis Group in Afghanistan. “This could open the ground for exploitation. They already have disputes.”

The similarly designed Afghan Local Police, formed in 2009, often serves as personal militias for the local powerbrokers who appoint them. In many places, it is accused of torture, extortion, extrajudicial killings and sexual abuse of young boys. Nothing in the new proposal suggests additional safeguards against such abuse.

The US military in Kabul did not respond to several requests for comment.

Western officials say militias undermine the Afghan state, but the policy is in line with the philosophy of Donald Trump, who has declared that America is not “nation-building again; we are killing terrorists”.

“This [policy] is the logical result of the Trump speech,” one western diplomat said. “If you declare you’re focused on killing terrorists, then killing becomes the centrepiece of your policy.”

Human Rights Watch criticised the expansion of irregular forces, saying it “could have enormously dangerous consequences for civilians”.

Vying for new militia money has already begun. One competitor is Gul Agha Sherzai, the minister for border and tribal affairs and a former powerful governor of Kandahar and Nangarhar. Sherzai is pushing to take control of the territorial force from the army, and create a new department within his ministry to command it.

In an interview, Sherzai said his ministry would ensure that government-funded armed groups only turn their weapons against insurgents, not local rivals. The only guarantee he could provide, however, was: “We will take signatures from tribal elders.”

As governor, Sherzai amassed great power and wealth, and his ambitions illustrate how powerbrokers see militia programs as tools for influence.

“Sherzai has been prone to arming people of his own tribe after he emerged as one of the most powerful men in the south after the fall of the Taliban,” Osman said.

In Nangarhar, one of four eastern provinces where the territorial force will be piloted, the tribal leaders who stand to benefit are known for misusing power, according to locals.

“They all work for their own benefit and create hatred among people,” one resident of the unstable Achin district said. “People fear them because they are strong and powerful, they have weapons, money and people in government.”

Some of the tribal leaders missing out on funding are already protesting.

Jalal Pacha, a former Taliban fighter turned local police commander, said that two local rivals picked for the militia program were linked to the insurgents. “They transfer boots, money and weapons to them,” said Pacha, who vowed his 60 armed men would fight if the new militias stood against him.

Haji Zahir Qadir, one of the most powerful men in Nangarhar, has formed a “unity council of the east” and called on lower-ranking tribal leaders not to support the government militias.

Qadir, who has claimed to have a fortune of $365m, has himself dabbled in ill-fated militia experiments. In 2015 his men, who were advised by American contractors, decapitated four Islamic State fighters in Achin and put their severed heads on display.

Nato first presented the territorial army idea to international donors in Kabul on 9 September, following a trip to New Delhi to study the Indian Territorial Army – which has also been dogged by accusations of abuse.

According to officials familiar with the meeting, European ambassadors first heard about the program when Nato commanders tried to get them to bankroll it.

“The ambassadors were surprised that Nato informed them about a new militia program only when the proposal was already sitting on President Ghani’s desk for approval,” an official said.

Wary of the tainted history of Afghan militias, the UN and European countries pushed back, and discouraged the president from approving the plans.

The full rollout has now been postponed until after parliamentary elections scheduled for 2018, and will be funded by the US Combined Security Transition Command – Afghanistan (CSTC-A).

Despite criticism, however, for President Ghani, there are obvious appeals to militias, which provide an affordable way to boost the security forces, which are shrinking under high desertion and casualty rates.

“President Ghani is just taking whatever he can at this point,” Osman said.

Additional reporting by Ghulamullah Habibi