WASHINGTON (AFP) - Global terror attacks soared by a third in 2014 with an 81 percent spike in the number of deaths, the United States said Friday in a grim annual report.

"The number of terrorist attacks in 2014 increased 35 per cent and total fatalities increased 81 per cent compared to 2013, largely due to activity in Iraq, Afghanistan, and Nigeria," the report says, adding that the war in Syria was a significant factor driving instability.

In total, there were 13,463 attacks in 2014 which killed 32,727 people, up on 9,700 assaults in 2013 in which 17,800 died.