Matthew Henman, manager of IHS Jane's Terrorism and Insurgency Center, said the number of terrorist attacks worldwide in 2013, 18,524, was 150 percent higher than in 2009.
For Syria, in the midst of brutal civil war, Henman said incidents of non-state attacks increased "due to a plurality of factors." "In 2012, we recorded 2,670 attacks," he said in a statement Thursday. "In 2013, that number jumped to 4,694."
For Iraq, however, the situation was worse. Henman said an increase in al-Qaida activity was dramatic.
"A key indication of the intensifying level of violence in Iraq was that the number of suicide attacks in the country quadrupled from 2012 to 2013, with the 2013 total almost triple that recorded in neighboring Syria and almost double that recorded in Afghanistan," he said.
Al-Qaida took over parts of western Anbar province in Iraq earlier this year. U.S. officials said political disputes in the country were being exploited by terrorist groups.
Al-Qaida fighters are also incorporated among rebels fighting against pro-government forces in Syria.