Two employees of the Indira Gandhi airport were detained following information they were planning to plant a mystery tissue box in an Air Deccan flight.
The two identified as Satya Dev and Musharat Hussain were immediately whisked away for questioning, informed sources said.
They said the two were detained after some airport staff overheard them discussing planting a tissue box on board an Air Deccan flight.
They were being interrogated by the Delhi Police and Central security agencies.
In a separate incident, four Bangaldeshis, believed to be illegal immigrants, have also been detained for questioning.
Security is at its highest level in the national capital following threats of terror, especially from Bangladesh-based outfits like Harkat-ul-Jehandi Islamia (HuJI) and Jamait-ul-Mujahideen Bangladesh (JMB).