Jan 16, 2015, Agencies: Security was stepped up at Mumbai's Chhatrapati Shivaji International Airport after another terror message was discovered by cleaning staff in a washroom in Terminal 1A.

The message warned of an Islamic State (IS) attack on January 26th.The incident is being probed by the Central Industrial Security Force (CISF).

A similar message was discovered on January 7 with the words, 'ATTECK BY ISIS 10/01/15 (sic),' scribbled by pen on a men's washroom wall.

According to a senior security official, quoted in NDTV, "The terminal is already under watch after Air India received threat and hijack calls earlier this month. After the T2 message, security was beefed up and today's messages will ensure that the security will be strengthened even further, especially on the city side."

With no CCTV cameras inside the washroom, the CISF is analysing footage from outside the washroom as well as getting experts to analyse the handwriting in both the notes.