The bomb alert sounded at Parliament House Complex on Thursday was a drill to check the preparedness of the security personnel.

As part of the drill, a packet was kept at a gate of the Parliament Annexe, which was spotted by security personnel after which an alert was sounded, sources said.

A bomb disposal squad of the National Security Guards was rushed to the high-security complex and it examined the bag.

Some light explosives were kept in the bag, sources said. "It was a security drill," Joint Secretary (Parliament Security) Kanwaljeet Deol said.

Soon after the bomb scare, security forces went on high alert in Parliament complex. Both houses were in session at the time of the scare.