Bogita Ongeri said today authorities recovered 100 kilograms of TNT from the vehicle which was intercepted at Dolo along Kenya's border with Ethiopia yesterday.
Ongeri said security forces had been tracking the car which had Kenyan registration and were aware that the suspected terrorists had unsuccessfully tried to gain entry into Kenya at another border point.
He said the five suspects killed are members of the Somali militant group al-Shabab, which is allied to al-Qaida. Al-Shabab carries out terrorist bombings in Kenya because Kenyan troops are in Somalia fighting the militants.