|A number of arrests have reportedly been made after the security breach [Reuters]
Sixteen Afghan soldiers have been arrested after 11 suicide vests were seized inside the defence ministry compound in Kabul, intelligence sources told Al Jazeera.
The compound, near the presidential palace, was sealed off after Tuesday's discovery.
The alleged plot was believed to be a simultaneous infiltration of the highly secured ministry headquarters and the detonation of 11 buses transporting government employees.
However, in a written statement issued on Tuesday, the Ministry of Defence rejected the reports.
The ministry asked that all media agencies, both domestic and international, only report on defence matters "after checking with responsible sections and people of this ministry."
Al Jazeera's James Bays, reporting from the Afghan capital, Kabul, said that while this information had not yet been formally released by the authorities, a number of arrests had already been made.
"Al Jazeera has been told by a high-level intelligence service source that the 11 suicide vests, packed with explosives and used by suicide bombers, have been found inside the ministry of defence headquarters - one of the most secure, heavily guarded buildings in the Afghan capital," said Bays.
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Attacks have increased in Afghanistan ahead of the US withdrawal from the country over the next two years.
"It is going to be of deep concern. The whole effort at the moment is trying to transition control to the Afghans, so that the international forces can pull back over next year and finally, most of them, depart Afghanistan by 2014," Bays said.
He said that while there was talk of transition at the moment, this security breach would worry commanders.
Shukria Barakzai, the country's former chairwoman of the defence committee, told Bays that she believed this was "evidence of high level infiltration".
"It must be high-profile people, which are behind such incidents which take place in the ministries from time to time," she said.
"It must be people who have links inside of the government, inside the presidential palace, inside the ministry of defence and other ministries..."
Barakzai said that this could be a high-level Taliban infiltration. She, however, did not rule out a foreign role.
This security breach comes a day after three NATO soldiers were killed by local security forces in two separate incidents.