The number of terror attacks and consequent deaths has declined for the first time since 2012, according to a new US State Department report.

The report counted 11,774 terror attacks in 2015, a decline of 13 percent compared to 2014. The number of people killed in the attacks was 28,328, a decrease of 14 percent.

But the report emphasized that despite the decrease, the global terrorist threat continued to grow rapidly in 2015 and is becoming increasingly decentralized and diffuse.

The decrease in the number of attacks and deaths was mainly due to fewer attacks in Iraq, Pakistan and Nigeria, according to the report. It also highlighted that terrorist attacks and consequent deaths increased in several countries, such as Afghanistan, Bangladesh, Egypt, the Philippines, Syria and Turkey in 2015.

Over 55 percent of all attacks took place in Iraq, Afghanistan, Pakistan, India and Nigeria, while 74 percent of all casualties from terror strikes occurred in Iraq, Afghanistan, Nigeria, Syria and Pakistan.

'Islamic State' biggest threat

The report highlighted the so-called "Islamic State" (IS) group, calling it the greatest terror threat globally as it maintained "a formidable force in Iraq and Syria, including a large number of foreign terrorist fighters."

But the report also said that the group's capacities are beginning to erode.

"ISIL did not have a significant battlefield victory in Iraq and Syria after May," the report said, using an alternative name for the group. "At the end of 2015, 40 percent of the territory ISIL controlled at the beginning of the year had been liberated."

The State Department cautioned however that even as (IS) group lost territory in Iraq and Syria, it has made gains in Libya as the country reels from lawlessness and instability.

bw/gsw (dpa, AFP)