NEW DELHI - India Tuesday put Mumbai airport on terror alert, following intelligence inputs that militants may be planning to target the terminal, sources said.

"The terror alert has been issued after intelligence agencies said that small planes or a helicopter may be used by terrorists to attack Mumbai's Chhatrapati Shivaji Airport. Intelligence officials have also asked that anyone hiring small planes or chopper be put through extensive verification processes," the sources said.

The terror alert says that private helipads and airports currently not in use or non-functional need to be monitored carefully, they said.

Mumbai became the target of a massive terror attack in November 2008 when 10 Pakistani militants entered the city through searoute and carried out a mayhem in which over 170 people were killed.

In July, a triple bomb blast hit Mumbai killing 19 people.