NSG, the country's elite counter-terror force, today warned that global terror outfits like the dreaded ISIS and al-Qaeda could join hands and launch a "multi-city multiple attack" on India.

The warning of a combined terror attack was sounded by National Security Guards (NSG) Director General J N Choudhury, who also called the 2008 Mumbai carnage that killed 166 people as just a "curtain raiser".

The NSG at the same time said it was fully prepared and will respond to whatever required and whenever required.

The NSG warning came a day after a top Army officer said that instances of waving of ISIS flags in Kashmir was a matter of concern and "deserves the highest attention of the security agencies" so that the youth in the Valley are prevented from being lured into the ranks of the jihadist organisation.