At least one tourist has been killed and 13 others injured in a suspected terror attack in the disputed Himalayan region of Jammu and Kashmir on Tuesday, authorities said.

The attack appeared to be a major shift in the regional conflict in which tourists have largely been spared from violence.

At least 20 people were feared killed after suspected militants opened fire on tourists in India's Jammu and Kashmir territory on Tuesday, three security sources said, the worst attack on civilians in the troubled Himalayan region for years.