New Delhi: Amid a heightened alert in the wake of Brussels terror attacks, security agencies have stepped up vigil at sensitive airports in the country with passengers being made to take off their footwear and belts and go through detailed frisking.

At major airports like Delhi, Mumbai, Bangalore, Hyderabad, Kolkata, Chennai and Ahmedabad, CISF and local police have shored up security apparatus and passengers are being observed and screened minutely with reintroduction of risk-based Secondary Ladder Point Check (SLPC) which entails frisking people before they enter the aircraft. The surveillance and patrol teams along the peripheries have also been asked to be extra cautious as passengers enter the terminal area unchecked.