UPDATE 8:30 pm- Air India said its flight, which was delayed due to bomb threat, took off at 7:50 pm local time. The passengers were shifted to another aircraft after the bomb threat earlier this afternoon.

After the passengers boarded the second aircraft, the flight was further delayed due to a fresh threat.

NEW DELHI: Passengers on a Kathmandu-bound aircraft of India's Jet Airways were forced to evacuate minutes before take-off from New Delhi on Wednesday due to a security alert, the second such incident this week on the same flight.

The plane's doors were closed and it was ready for take-off when the alert was raised, according to a Jet Airways spokesman. All 122 passengers and seven crew members were asked to leave the plane and security agencies were investigating.

The incident comes two days after the same Jet Airways' Delhi-Kathmandu 9W 260 flight was delayed due to a security scare, but investigations later found nothing unusual.

"It is the same flight. This is something that doesn't happen normally," a company spokesman said.

Police at Delhi's international airport were not immediately available for comment on what caused the security scare. Indian media said police received an anonymous call warning bombs were on two aircraft.

The other aircraft, operated by Air India, was also headed to Nepal's capital Kathmandu. The plane was taken to a bay area and security personnel screened the baggage, the company said on its Twitter account.

Security was been beefed up across India this week because of Tuesday's Republic Day parade, at which French President Francois Hollande was the guest of honour.