Jitters, vigilance over possible July 4 terrorist threat

A false alarm over a shooter at the Navy Yard in Washington Thursday brought a rapid and massive response from police who are especially on high alert for possible terrorist acts during the July 4 weekend.

While authorities are wary of raising unnecessary anxiety during the holiday, White House spokesman Eric Schultz noted that the Department of Homeland Security and FBI have alerted local authorities to be especially vigilant for the holiday weekend.

Even after the Navy Yard threat proved to be unfounded, Washington Police Chief Cathy Lanier she thought it is better to act than not, emphasizing that authorities mean it when they encourage people to "see something, say something."

DHS Secretary Jeh Johnson has underscored the point by encouraging law enforcement "to be vigilant and prepared."

Rep. Pete King, a senior member of the Homeland Security Committee, told Newsday, "This is the highest level of concern since 9/11" and called on Americans to keep their eyes open.

The New York Republican says he is not aware of any "specific threat against any particular part of the country," but notes that recent terror attacks in France, Tunisia and Kuwait linked to the Islamic State, combined with a series of local arrests of suspected terrorists, signal a cause for alarm.

As a result, federal and local authorities are stepping up security in response to a bulletin by the Department of Homeland Security and FBI regarding ongoing attack threats by the Islamic State and other homegrown extremists. Such advice is frequently sent out in advance of major U.S. holidays as a precaution.

In symbol-rich Washington, where tens of thousands of people are expected at the National Mall for one of the largest firework displays in the country, special police patrols will keep an eye on potential targets like landmarks, financial institutions, houses of worship, hotels and theaters, police said.

Additional plainclothes officers, radiation detection units, bomb-sniffing canines and surveillance aircraft will also be deployed.

"The safety of residents and visitors to the city during this special event is always at the forefront of our planning and response efforts. Recent global events require a vigilant and proactive posture," said Gwendolyn Crump, director of communications for the D.C. Metropolitan police.

In New York City, the police will deploy "in excess of 7,000" officers in addition those patrolling the rest of the city, John Miller, NYPD Deputy Commissioner of Intelligence and Counterterrorism, told "CBS This Morning." He called it one of their biggest operations ever.

"I think if you look at history, they're looking at big events, they're looking at symbolic dates. They're looking at military, police, intelligence," Miller said.

He said officers are trained to look for anomalies in people's behavior, such as those who spend more time looking at security or looking out for police than at a parade float or fireworks display.

In Los Angeles, police declined to provide details of additional security steps being taken, but a spokeswoman, Officer Liliana Preciado, said the department is preparing for any threat. "We do have enough resources available and we will have enough officers out there," Preciado said.

In Boston, the city plans to increase the number of officers on duty to provide security and crowd control, said Officer Rachel McGuire, a department spokeswoman.

Authorities have also banned drones from the area for July 3 and July 4, saying they cause undue concern, boston.com reports.

Massachusetts State Police spokesman David Procopio told The Boston Globe there will be an "extremely rigorous, multi-layered security plan in place" for the weekend events on Boston's Esplanade.

In New Orleans, the local FBI office will have extra agents on duty and have warned residents to be on the lookout for "suspicious activity" over the long weekend, but not to alter their holdiay plans, The Times-Picayune reported.

"Here in New Orleans, our posture will be similar to the posture we take during special events like Mardi Gras, Jazz Fest or the Sugar Bowl," Assistant Special Agent In Charge Andrew Ludlum told the newspaper.

Contributing: Gregg Zoroya