Officials say that U.S.-funded development firms are beginning to shut down massive reconstruction projects in Afghanistan because the country's government refuses to rescind a ban on their use of private security guards, the Washington Post reports.

One U.S. official tells the paper that working without private guards would "be catastrophic," while another official says the ban could affect nearly $1.5 billion in ongoing reconstruction work.

Officials say if the Afghan government goes through with the ban, it could have far-reaching effects on the military campaign against the Taliban because programs to assist Afghan farmers and improve local governments would be affected.

Afghan officials say private security contractors hired by U.S. firms operate with little oversight and sometimes function as private militants.

"If we don't have private security, we can't operate in Afghanistan," one development executive told the Post.

The ban goes into effect Dec. 17.