Sixteen people have been arrested in the Afghan capital, Kabul, after plans for an apparent mass suicide attack were foiled.
Intelligence officials have told the BBC that 11 suicide jackets were seized in the Ministry of Defence.
They say the attacks would have caused significant loss of life if they had gone ahead.
The BBC reports some of those arrested are reported to be soldiers in the Afghan National Army.
The jackets were seized on Monday afternoon from three separate rooms around a ministry car park, less than a kilometre from the presidential palace.
The arrests came as people wearing the uniforms of Afghan security forces killed one US and two British soldiers in separate incidents, in Paktika province and Lashkar Gah respectively.
Attacks on US and Nato forces have increased since the burning of Korans by US troops in February and the murder of several Afghan civilians by a US staff sergeant on 11 March.