KABUL, Afghanistan — Afghanistan's president is issuing an ultimatum to thousands of private security contractors he says are undermining his nation's army and police force: Cease operations in four months.

President Hamid Karzai's strident decision, announced Monday by his spokesman, is expected to meet resistance from NATO officials who rely heavily on private security companies to guard convoys and installations across the country.

With complaints that they are poorly regulated, reckless and effectively operate outside local law, such operators have become a point of contention between the Afghan government and U.S. and NATO coalition forces and the international community.

"The security companies have to go," presidential spokesman Waheed Omar said Monday as he announced the deadline.

In Washington, Pentagon spokesman Bryan Whitman questioned whether a four-month deadline was realistic.

"I think everyone looks forward to the day when private security companies can be eliminated altogether from Afghanistan because the security situation is such that they are no longer needed," Whitman said.

"Until that time, though, we're going to continue to work with the government of Afghanistan to improve the oversight and management as well as developing plans to progressively reduce their numbers as security conditions permit."

Maj. Joel Harper, a U.S. military spokesman in Kabul, said the military supports Karzai's goal of eliminating private security companies, but that doing so requires "a deliberate process that recognizes the scale and scope of the issue."

Karzai pledged in his inauguration speech in November to shutter both foreign and domestic security contractors by November 2011.

Now, according to Omar, Karzai is expected to take action more quickly and issue a decree to outline how the companies should cease operations.

"Within four months, all private security companies will be disbanded," Omar said without providing details of Karzai's expedited decree.

In Washington, State Department spokesman P.J. Crowley said Monday that U.S. officials want clarification and more details.

"At this moment, we believe there is still a need for private security companies to continue to operate in Afghanistan," Crowley said, adding that the U.S. agrees security should eventually be an entirely Afghan operation. "Four months is a very challenging deadline."

The U.S. military set up a task force in June to tighten regulation and oversight of its security contractors.

"Since the Afghan army and the Afghan police are not quite at the stages of capability and capacity to provide all the security that is needed, private security companies are filling a gap," Brig. Gen. Margaret Boor said Monday before the new deadline was announced.

Boor said private security contractors can be phased out only as the security situation improves -- a hard target given worsening security in recent months in areas of northern and central Afghanistan that had previously been relatively safe.

Though the U.S. task force is new, Boor said it is already taking steps to improve oversight of security firms, including registering all contractors and ensuring they have the necessary qualifications and receive training on appropriate use of force.

Karzai's spokesman said greater regulation of the companies would not solve the problem.

"It's not about regulating the activities of the private security companies, it's about their presence and it's about the way they function in Afghanistan," Omar said. "It's about the way they have developed into alternative forces."

In a speech earlier this month, Karzai urged the U.S. and NATO to stop supporting private security companies, which he claims have created a separate security apparatus in Afghanistan. Afghan authorities have especially complained about security firms that guard NATO supply convoys, alleging they are trigger-happy and sometimes fire at civilians without provocation.

"We cannot tolerate these companies, which are like a parallel structure with our forces," Karzai said in the speech in the capital. "We cannot have police, army and -- at the same time -- another force as private security companies."

The president estimated that 30,000 to 40,000 people worked for security companies.

"They have created security problems for us," Karzai said. "Whoever is working in these private security companies, they are not working for the benefit of Afghan national interests. ... If they really want to be at the service of Afghans, they should join Afghan National Police."

The Afghan Interior Ministry has 52 security firms licensed, but some older contracts are still being completed by unlicensed firms, according to the U.S. military. According to the Pentagon, there are about 26,000 private security contractors working in Afghanistan for 37 different companies -- 17 of them Afghan-owned. The State Department and USAID rely the most heavily on the companies to provide their employees security.

Private security contractors in Afghanistan are subject to Afghan law, unlike the situation that persisted through most of the war in Iraq, where those working for the U.S. military were immune from prosecution by Iraqi authorities.

Contractors in Iraq lost their immunity when a U.S.-Iraqi security pact took effect Jan. 1, 2009. The move to tighten oversight followed Iraqi outrage over a Sept. 16, 2007, shooting in which 17 Iraq civilians were killed in a Baghdad square. Blackwater said its guards were protecting diplomats under attack before they opened fire, but Iraqi investigators concluded the shooting was unprovoked.

Contractors in Afghanistan also have been in the spotlight on several occasions in Afghanistan.

In 2009, a private security contractor hired to protect the U.S. Embassy in Kabul was exposed for holding lurid parties flowing with alcohol, with guards and supervisors photographed in various stages of nudity. A U.S. government investigation also found Amorgroup employees frequented Kabul brothels.

In February, U.S. Senate investigators said the contractor formerly known as Blackwater hired violent drug users to help train the Afghan army and declared "sidearms for everyone" -- even though employees weren't authorized to carry weapons. The allegations came as part of an investigation into the 2009 shooting deaths of two Afghan civilians by employees of the company, now known as Xe.