Among the companies whose operations are being dissolved are Xe (formerly known as Blackwater), NCL, FHI, White Eagles and other small companies, spokesman Waheed Omer said. Both international and domestic companies were affected.

Weapons and ammunition belonging to these companies has been seized, he said.

Xe has several operations in Afghanistan, some of which will not be immediately affected by the decision. While Xe's transportation and highway security operations have stopped, it will continue to offer security for embassies.

"Until we have Afghan security forces up and running, private security companies will continue to operate and serve in training and protection of foreign embassies," Omer said.

Of the eight companies named during the press conference, some have already disbanded, while others are in the process of doing so, Omer said.

There were 52 registered private security companies in Afghanistan, half of them international, according to the interior ministry. Now there are 44 private security companies operating in the country.

Afghan President Hamid Karzai issued a decree last month disbanding all private security firms within four months.