A bag with suspected RDX was found at Delhi airport in the early hours of Friday, leading to restrictions on passenger movement for a couple of hours, officials said.

The black bag, first detected around 1 am by a CISF guard in the arrival area of Terminal-3, has now been kept in a cooling pit.

Preliminary inputs suggest the bag contained RDX. It was checked by an explosive detector and a dog. However, the exact nature of the explosive is being ascertained, sources said.

It could be an explosive or an improvised explosive device (IED), but it is not clear at present, the sources said.

Delhi Police said it received a call around 1 am, following which the bag was found at arrival gate two of the terminal.

'The bag was removed with the help of the CISF. It has not been opened yet. It seems like there are some electric wire inside it. We have increased the security on the airport premises,' said Sanjay Bhatia, deputy commissioner of police (airport).

The incident caused panic among passengers who were not allowed to exit the terminal for some time, sources at some airlines said.

Officials said personnel of the CISF and Delhi police conducted a complete anti-sabotage check of the Indira Gandhi International airport after which passenger movement was allowed around 4 am.