Afghan security officials say they have foiled a huge attack in the capital Kabul, as they gave details of the seizure of 10 tonnes of explosives.
The explosives were found in a truck seized along with five militants in an operation last Sunday, a National Directorate of Security spokesman said.
The group was planning to kill the second vice-president, Mohammad Khalili and attack crowded areas, he said.
The arrests happened during a wave of insurgent attacks around the country.
The discovery was kept quiet because of the sensitive nature of the operation, NDS spokesman Shafiqullah Tahiri said.
The explosives, stuffed in 400 bags and hidden under piles of potatoes, were to have been used in a massive attack targeting crowded areas of the capital, he added.
The spokesman said the five suspects had links with Pakistan's main intelligence organisation, the Inter-Services Intelligence agency, or ISI, and were acting on the orders of two Taliban commanders.
Afghanistan has often accused the ISI of involvement in supporting anti-government insurgents in Afghanistan.
A video detailing the group's plans was also found, along with suicide vests and weapons, the spokesman said.
"If this amount of explosives had been used, it could have caused large-scale bloodshed," Mr Tahiri said.
Earlier, another spokesman said the men - three Pakistan citizens and two Afghans - were thought to belong to the Pakistan-based Haqqani insurgent network.
The mainly Afghan Pashto group operates out of the northwestern Pakistani tribal areas, and is seen as linked to, but separate, from the Afghan Taliban.
Last week, 51 people died in a wave of co-ordinated attacks by insurgents in Kabul and three other provinces.