High ranking members of the NYPD walk along the finish...

High ranking members of the NYPD walk along the finish line area of the New York City Marathon with an event organizer in Manhattan. (Oct. 31, 2013) Credit: Charles Eckert

The anti-terrorism operation at Sunday's New York City Marathon will be among the largest ever carried out across the five boroughs, as authorities employ new tactics in response to the Boston Marathon bombings, officials said.

Federal authorities and police are treating the marathon as a potential terrorist target, bolstering security to an unprecedented level for the event and working closely with U.S. intelligence agencies to sniff out any plots, according to a federal law enforcement source in New York with knowledge of the security measures and a city police official.

New elements of the plan include more bomb-sniffing dogs on patrol, high-tech explosives detection equipment, police boats and divers stationed on the city's waterways, intensive video surveillance, and the presence of thousands of additional private security workers, police officers and plainclothes law enforcement agents.

"Boston made us take a hard look at the way we secure these kinds of events," the federal law enforcement source said. "Nothing's being taken for granted in terms of security or threat assessment."

The sources described details of the security plan on condition of anonymity because they were not authorized to discuss them publicly. City and federal officials also declined to discuss security arrangements.

Spectators who want to cheer from the marathon finish line will be screened for weapons and explosives. Any bag carried within blocks of the racecourse will be searched. And participants in the marathon's opening parade will not be allowed to march with bags, race officials said.

Authorities say the two bombs detonated at the Boston Marathon finish line April 15 -- which killed three people and injured more than 260 -- have transformed security procedures at major events across the country.

"It will be tight," police Commissioner Ray Kelly said of security near the finish line. "It always is tight, but obviously we're going to pay particular attention to that this year."

Major professional sporting events, such as the Super Bowl and World Series, have been treated as potential targets since the Sept. 11, 2001, terror attacks. But the New York and Boston marathons are far more difficult to secure because of their 26.2-mile courses, which snake through different urban landscapes and call for a range of security tactics.

Some stretches of the New York course wind through streets lined with skyscrapers, the windows of which can serve as sniper nests. Other parts of the course are exposed to subway grates and drains, under which bombs can be hidden.

Three private security firms were added by the New York City Road Runners Club, which operates the marathon, as well as extra K-9 and helicopter units, apart from public security operations and NYPD counterterror units. There will also be a separate marathon communications center in Central Park, similar to an air traffic control center, officials said.

"We've worked very hard on this," New York Road Runners executive vice president Peter Ciaccia said. "We're totally prepared."

Marathon officials said they will spend about $1 million on security, double their normal amount. So far, they say, there have been no credible threats made against the marathon.

Other changes this year include a longer list of prohibited items, including backpacks, strollers and water carriers called Camelbacks. Also, more areas near Central Park, open in years past, will be closed to the public.

This year's 43rd running of the marathon has roughly 60,000 entrants, with 45,000 to 48,000 runners expected to start the race. Superstorm Sandy led to the cancellation of last year's race.

"This is the first time some of the newer strategies for securing an event of this size will be deployed," the federal source said. "The number of resources . . . will be staggering."

Authorities will be patrolling the marathon with the lessons of the Boston bombings still fresh in their minds.

Armed with how-to instructions found on the Internet, authorities said, brothers Dzhokhar Tsarnaev, 20, and Tamerlan Tsarnaev, 26, ethnic Chechens from Russia, built homemade pressure-cooker bombs loaded with BBs and nails that they planted near the marathon's finish line.

Dzhokhar Tsarnaev faces 30 federal charges, including using a weapon of mass destruction, and could receive the death penalty if convicted. Tamerlan Tsarnaev was killed during a shootout with police as authorities closed in on the brothers after the bombings.

"There is a tremendous responsibility coming after last year and coming after Boston, to have the very best day we can," NYC Marathon director Mary Wittenberg said.

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