Extremists in Iraq, Afghanistan and Nigeria unleashed a savage rise in violence between 2013 and 2014, according to new statistics released by the US State Department.
Attacks largely at the hands of the Islamic State (IS) and Boko Haram raised the number of terror acts by more than a third (35%), nearly doubled the number of deaths and nearly tripled the number of kidnappings.
The figures contained in the department's annual global terrorism report say that nearly 33,000 people were killed in almost 13,500 terrorist attacks around the world in 2014.
That was up from just over 18,000 deaths in nearly 10,000 attacks in 2013, it said.
Twenty-four Americans were killed by extremists in 2014 and abductions soared from 3,137 in 2013 to 9,428 in 2014, the report said.
It attributed the rise in attacks to increased terror activity in Iraq, Afghanistan and Nigeria and the sharp spike in deaths to a growth in exceptionally lethal attacks in those countries and elsewhere.
There were 20 attacks that killed more than 100 people each in 2014, compared to just two in 2013, according to the figures.
Among the 20 mass casualty attacks in 2014 were the December attack by the Pakistani Taliban on a school in Peshawar, Pakistan that killed at least 150 people and the June attack by IS militants on a prison in Mosul, Iraq, in which 670 Shiite prisoners died.
At the end of 2014, the prison attack was the deadliest terrorist operation in the world since Sept ember 11, 2001, according to the report.
Terror attacks took place in 95 countries in 2014, but were concentrated in the Middle East, South Asia and west Africa.
Iraq, Pakistan, Afghanistan, India and Nigeria accounted for more than 60% of the attacks and, if Syria is included, roughly 80% of the fatalities, the report found.
The rise in kidnappings is mainly attributable to sharp increases in mass abductions by terrorist groups in Syria, notably the Islamic State and the al Qaida-linked al-Nusra Front. In Nigeria, Boko Haram was responsible for most, if not all, of the nearly 1,300 abductions in 2014, including several hundred girls from a school in Chibok.
By contrast, fewer than 100 terror-related kidnappings were reported in Nigeria in 2013, according to the report.
Today's report noted the "unprecedented seizure" of territory in Iraq and Syria by IS in 2014 along with its continued demonstrated ability to recruit foreign fighters to join its cause and the emergence of self-proclaimed affiliates notably in Libya, Egypt and Nigeria.
It also pointed out a rise in the number of so-called "lone wolf" attacks in the West and the use of more extreme methods of violence by terrorists to repress and frighten communities under their control.
At the same time, the report said regional and international efforts to counter the Islamic State and other groups were starting to make inroads.