At least 26 people were killed and 17 others wounded when gunmen opened fire on tourists in Indian-controlled Kashmir, the worst assault in years targeting civilians in a restive region that has seen an anti-India rebellion for more than three decades.

India's Prime Minister Narendra Modi says the gunmen behind a terrorist attack on tourists in the Kashmir region "will not be spared!"

The fear of more terror attacks targeting tourists is likely to keep away many people from visiting Kashmir for some time, as only 30 percent of those surveyed are likely to take a trip to the Valley.