KABUL, Afghanistan — Afghanistan's president issued a decree Tuesday formalizing his four-month deadline for private security companies to disband -- a move likely to dismay NATO and the U.S. military that rely on such firms to protect convoys and bases.

Security operators -- both Afghan and foreign -- have become a point of contention between the government and coalition forces and the international community as complaints have mounted that the firms are poorly regulated, reckless and effectively operate outside local law.

According to the decree, the tens of thousands of security contractors currently working in Afghanistan will have to either join the Afghan police force or cease operations by the deadline.

It does provide an exception for private security firms working inside compounds used by international groups, including embassies, businesses and non-governmental organizations.

"They will have to stay inside of the organization's compound and will have to be registered with the Interior Ministry," the decree states.

All security outside of these compounds will be provided by Afghan security forces, as will all security for supply convoys for international troops, the decree says.

The deadline was first announced Monday by Karzai's spokesman but no details were available until the decree was formally issued.

It is expected to meet resistance from NATO officials who rely heavily on private security companies to guard convoys and installations across the country. Officials in Washington have questioned whether a four-month deadline is realistic.

"We have a common goal in eliminating the need for private security companies and transitioning" to a point where they will be under Afghan government control, Defence Department spokesman Bryan Whitman said Tuesday in Washington. But, he said, U.S. officials want to do it "in a deliberate way through a process that recognizes the scale and scope of the challenge."

Whitman did not say how long he thought that would take. But a task force set up in June to better regulate and oversee private security operations is only now just getting to its full strength of some two dozen staff, said a senior defence official who spoke only on condition of anonymity because of the sensitivity of the issue.

The group, called Task Force Spotlight, has a previously scheduled forum at the end of this month for heads of private security companies in which officials plan to lay out policies and procedures the companies are expected to follow.

A spokesman for NATO forces said that the transition is a goal that should not be rushed into.

"This is an undertaking that requires a deliberate process," Maj. Joel Harper said, adding that it should happen "under a timeline that recognizes the scale and scope of this issue will take time to fully implement."

Karzai pledged in his inauguration speech in November to shutter both foreign and domestic security contractors by November 2011. This decree significantly speeds up the timeline.

The government has estimated that 30,000 to 40,000 armed security contractors are working in the country.

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. About half of the companies are Afghan-owned.

About 37 companies are working with the U.S. government, totalling about 26,000 armed security contractors. The majority of those work for the military, though some are employed by the State Department and the U.S. Agency for International Development, according to the military.

Any security contractor currently registered with the government will have the option to sell their weapons and equipment to the police or take them outside of the country, according to the decree. Any unlicensed contractor will have their weapons and equipment seized.

The issue of private security contractors was a topic of talks that Karzai had earlier in the day with U.S. Senator John Kerry, chairman of the Senate Foreign Relations Committee, who is visiting Afghanistan, along with Gen. David Petraeus, the top commander of U.S. and NATO forces, and U.S. Ambassador Karl Eikenberry. The U.S. officials are pushing Afghan officials to battle government corruption.

A statement Tuesday by Karzai's office said he recently sent a letter to President Barack Obama saying the war strategy needed to be reviewed. Without mentioning neighbouring Pakistan, Karzai said in the letter that there is a need to focus on the "roots and sanctuaries" of terrorism outside Afghanistan instead of only fighting the war in Afghan homes and villages.

Also Tuesday, officials said bomb attacks killed three U.S. service members and three Afghan civilians.

Two of the Americans were killed in a bombing in the east, while the third was killed in the west, NATO said. It did not provide details on where or how they were attacked.

Meanwhile, a bomb hidden on a motorbike killed two Afghan street cleaners early Tuesday in eastern Ghazni province. The bomb, which was remote-detonated, appeared to be targeting a police truck that was driving down the street in Ghazni city, said Ismail Jahangir, a provincial government spokesman. The explosion also wounded one police officer and four other civilians, he said.

In Kandahar province in the south, a tribal elder and district council member was killed early Tuesday by a bomb planted in his office in the border town of Spin Boldak, according to the border police chief for the area, Gen. Razaq Khan.

The bomb had been hidden under a cushion that exploded when the elder, Zekirya, leaned against the it, Khan said.

Also, NATO reported that its forces killed a Taliban operative named Bilal who had ties to the network involved in last month's killing of two U.S. sailors in central Afghanistan. The alliance said it is unknown what role, if any, he played in their deaths.

Bilal was killed Monday in Logar province's Charkh district, NATO said.