Washington - Terrorist attacks worldwide surged by more than a third and fatalities soared by 81 per cent in 2014, a year that also saw the Islamic State in Iraq and Syria (ISIS) eclipse Al-Qaeda as the leading militant group, the US State Department said.
In its annual report on terrorism, the department also charted an unprecedented flow of foreign fighters to Syria, often lured by ISIS' use of social media.
Taken together, the trends point to a sobering challenge from militant groups worldwide to the United States and its allies despite severe blows inflicted on Al-Qaeda, author of the Sept 11, 2001 attacks in Washington and New York.
The State Department report said there were 13,463 terrorist attacks last year, a 35 per cent jump from 2013, resulting in more than 32,700 deaths. More than 9,400 people were also kidnapped or taken hostage by militants, triple the rate of the previous year.
But there was some good news: Militant activity decreased in some countries, including Pakistan, the Philippines, Nepal and Russia.
The report said the global increase in terrorist attacks was mostly due to events in Iraq, Afghanistan and Nigeria.
ISIS was particularly lethal. A June 2014 attack on a prison in Mosul, Iraq, in which the group killed 670 Shi'ite Muslim prisoners, "was the deadliest attack worldwide since Sept 11", the report said.
The State Department's coordinator for counter-terrorism, Ms Tina Kaidanow, told a news conference last Friday that weak or failed governments allowed the terrorist groups to thrive. And while the US still worried about Al-Qaeda, the growing concern was the number of groups aligning themselves with ISIS across the globe.
As of late December, more than 16,000 foreign terrorist fighters had travelled to Syria, exceeding the rate of those who travelled to Afghanistan and Pakistan, Iraq, Yemen or Somalia.
The State Department also said Iran continued its "terrorist-related" activity last year and still provided broad military support to Syrian President Bashar al-Assad's crackdown on political opponents.
Its assessment suggests that neither the election of President Hassan Rouhani nor the prospect of a nuclear accord with the US and its negotiating partners has had a moderating effect on Iran's foreign policy in the Middle East.