Relations between India and Pakistan are cratering following a deadly attack in the disputed Himalayan region of Jammu and Kashmir that left more than two dozen tourists dead.

The Pakistani government said that if India followed through on a threat to block rivers it would take it as “an act of war.”

At least 20 people were feared dead after suspected militants opened fire on them in India's Himalayan territory of Jammu and Kashmir on Tuesday, with officials saying it was one of the deadliest such attacks in recent times.