WASHINGTON - Terrorist attacks worldwide shot up more than 25 percent last year, killing 40 percent more people than in 2005, particularly in Iraq, where extremists used chemical weapons and suicide bombers to target crowds, the State Department said yesterday.

Among countries, it said, Iran remains the biggest supporter of terrorism, with elements of its government backing groups throughout the Mideast, notably in Iraq, giving material aid and guidance to Shiite insurgent groups that have attacked Sunnis, U.S. and Iraqi forces.

In its annual global survey of terrorism, the State Department said 14,338 attacks took place in 2006, mainly in Iraq and Afghanistan - 3,185 more than in 2005, or a 28.5 percent increase.

Those strikes claimed a total of 20,498 lives, 13,340 of them in Iraq - up by 5,800, or 40.2 percent, over last year, it said.

Despite the grim figures, department officials pointed to some successes in the antiterror effort, including improved counterterrorism cooperation with various nations and the thwarting of numerous plots, notably plans to down transatlantic jets.

"Serious challenges do remain, there's no question about that," said acting counterterrorism coordinator Frank Urbancic. "This is not the kind of war where you can measure success with conventional numbers. We cannot aspire to a single decisive battle that will break the enemy's back, nor can we hope for a signed peace accord to mark victory."

The report partly attributes the higher casualty figures to a 25 percent jump in the number of nonvehicular suicide bombings targeting large crowds. That overwhelmed a 12 percent dip in suicide attacks involving vehicles.

In Iraq, the use of chemical weapons, seen for the first time in a Nov. 23, 2006, attack in Sadr City, also "signaled a dangerous strategic shift in tactics," it said.

With the rise in fatalities, the number of injuries from terrorist attacks also rose, by 54 percent, from 2005 to 2006, and the number of wounded doubled in Iraq over the period, according to the department's Country Reports on Terrorism 2006.

The numbers were compiled by the National Counterterrorism Center and refer to deaths and injuries sustained by "noncombatants," with significant increases in attacks targeting children, educators and journalists.

"By far the largest number of reported terrorist incidents occurred in the Near East and South Asia," said the 335-page report, referring to the regions where Iraq and Afghanistan are situated. "These two regions also were the locations for 90 percent of all the 290 high-casualty attacks that killed 10 or more people," it said.

The report said 6,600, or about 45 percent, of the attacks took place in Iraq, killing about 13,000 people, or 65 percent of the worldwide total of terrorist-related deaths in 2006. Kidnappings by terrorists soared 300 percent in Iraq over 2005.

Afghanistan had 749 strikes in 2006, a 50 percent rise from 2005, according to the report.

However, it also detailed a surge in Africa, where 420 attacks - compared with 253 in 2005 - were counted last year, largely due to turmoil in or near Sudan, including Darfur, and Nigeria, where oil facilities and workers have been targeted.

As in previous years, the 2006 report identified Iran as the "most active state sponsor" of terror, accusing the Islamic republic of helping plan and foment attacks to destabilize Iraq and derail Israeli-Palestinian peace efforts.

Read the annual global survey of terrorism via http://go.philly.com/globalterrorEndText