Terrorist violence exploded around the world last year, driven by a surge in attacks by the Islamic State extremist group in the Middle East and Boko Haram in West Africa, the State Department said in a report Friday.
The number of terrorist attacks jumped 35%, to 13,500, while the number of fatalities soared 81%, to 33,000, the report says. A major factor was an increase in especially deadly attacks, including 20 assaults that killed 100 or more people.
The surge in lethality comes as governments have collapsed or come under attack in parts of the Middle East and Africa, including in Syria, Iraq, Yemen, Libya and Nigeria.
The number of people kidnapped or taken hostage tripled, to more than 9,400, largely at the hands of Islamic State and Al Nusra Front in Syria and Boko Haram in Nigeria.
Tina Kaidanow, the State Department's counter-terrorism coordinator, said much of the terrorist violence was confined to a few troubled nations.
But she said the threat of "lone wolf attacks" is growing in the West, in part because Western governments are making it harder for recruits to travel to join extremist groups abroad. Still, an estimated 16,000 foreign fighters joined Islamic State in Syria and Iraq in 2014.
The extremist groups' effective outreach on social media and the Internet is also driving zealots to plot and launch attacks, Kaidanow said. She cited lethal assaults last year by gunmen in Ottawa and Sydney.
The statistics came in an annex to the State Department's annual "Country Reports on Terrorism," which was released Friday.
At a news briefing, Kaidanow argued that the negative trends, while troubling, aren't a good measure of how well the Obama administration's counter-terrorism programs have performed.
Kaidanow said the administration has helped other nations improve border security, strengthen counter-terrorism laws and increase information sharing to sharpen their defenses against terrorist violence.
"We have been effective in dealing with the capabilities of our partners globally," she said. "This is not a battle… the United States can undertake alone."
She said the threat posed by the core Al Qaeda network continued to diminish in 2014 after the deaths and arrests of leaders in Pakistan, Afghanistan and Yemen.
Al Qaeda also lost "momentum," the report says, because of the growing prominence and allure of Islamic State, which says it intends to set up Islamic caliphate across the Muslim world.
Even so, the report says, Al Qaeda continues to provide inspiration for lethal affiliates, including Al Qaeda in the Arabian Peninsula, based in Yemen; Al Qaeda in the Magreb, based in North Africa; Al Nusra Front in Syria; and the Shabab, which operates in East Africa.
The report also says Iran has been "dramatically bolstering" the capabilities of President Bashar Assad's government in Syria, "prolonging the civil war… and worsening the human rights and refugee crisis there."
Iran has sent arms to Syria, including through Iraqi airspace, in violation of United Nation Security Council resolutions, the report says.
Although the administration has tacitly cooperated in some ways with Iran in the fight against Islamic State in Iraq, the State Department complained about Iran's approach. It cited the role of the Quds Force, an elite branch of the Islamic Revolutionary Guard Corps.
"Iran has used Iraqi Shia militants and high-profile appearances by Quds Force officials on the front lines of Iraq to claim credit for military successes against [Islamic State] and to belittle coalition airstrikes and U.S. contributions to the government of Iraq's ongoing fight against [Islamic State]," the report says.
The report also cites Iran's support of terrorist groups, including Hezbollah, Hamas, Iraqi Shiite militant groups, and Palestinian Islamic Jihad.