Separate security incidents in New York and Boston Tuesday morning highlighted jittery nerves around the nation a day after twin bombings killed three and injured more than 170 at the Boston Marathon.
A portion of New York's LaGuardia Airport was evacuated briefly Tuesday morning following a report of suspicious wiring.
Ron Marsico of the Port Authority of New York and New Jersey, which runs the airport, says wires protruding from a fluorescent light fixture led someone to call authorities, prompting the closure of the upper level of the airport's central terminal building at 10:30 a.m.
The all-clear was given about an hour later and passengers were allowed back into the terminal.
People tweeted photos of travelers outside the Central Terminal, standing with luggage during the evacuation.
Steve Coleman, a spokesman for the Port Authority of New York and New Jersey, said in an e-mail "Shut down at LaGuardia... Tense times on the East Coast," according to Bloomberg News.
At Boston's Logan Airport, a security scare focused on a US Airways flight that originated in Philadelphia.
The plane was delayed and searched shortly after landing at Boston, when a popping sound was heard from a carry-on bag, reported CBS Philadelphia.
The US Airways flight 1716 left Philadelphia International Airport at 9:24 a.m. and landed at Logan International Airport at 10:16 a.m.
According to sources, a popping noise was heard coming from a carry-on bag and someone reported seeing what was believed to be smoke.
WPVI TV of Boston reported a baggage handler in Boston initially raised the alarm, after becoming concerned about a piece of checked luggage from that flight after it fell off a baggage cart and made a noise that sounded like a bang.
Investigators, along with a bomb-sniffing dog, searched the plane and several bags on the plane. Fire trucks, ambulances and other emergency personnel were on stand-by near the plane.
Massport, which operates Boston Logan, did not give specific details about the incident but issued a brief statement:
"Out of an abundance of caution a US Airways flight was remotely parked at the airfield while a bag on board was examined. The passengers were bused to the terminal, the baggage was deemed harmless, and the flight taxied to the gate. Airport operations were not impacted."
According to passenger Andy McKenchie, the flight was "surrounded" after arriving at Logan; 30 minutes later he tweeted passengers were being bussed to the terminal.
"All passengers waiting from the US Airways flight in Boston are pretty relaxed. Thankfully no one seems too upset," he tweeted.
Meanwhile, preparations for another marathon have incorporated increased security. Long Island Press reported Long Island was on high alert after the bombings and would be taking extra precautions in the lead-up to the Long Island Marathon Weekend, just two weeks away on May 3 to 5.
Nassau County Executive Ed Mangano said Nassau police were "in constant contact with the FBI and the NYPD."
"We will be holding a security meeting this Wednesday with subsequent security briefings in the weeks leading up to our Long Island Marathon," he said.
Suffolk County Police Deputy Chief Kevin Fallon, that department's chief spokesman, said officers are focusing on Long Island Rail Road stations, malls and sports arenas with backup from bomb-sniffing dogs.
"Patrols will include having officers exiting their vehicles and walking through the transportation facilities," he said. "Police have no reason to believe that a similar incident will occur in Suffolk...but the department is taking precautionary measures."
Security in New York City remains tight at high-profile landmarks, hotels and subway stations in the aftermath of Boston attack.
Areas like Times Square, Rockefeller Center, Grand Central, the Empire State Building, the United Nations and the World Trade Center site were being especially monitored, police told CBS New York.
"We are asking all New Yorkers to remain vigilant," Mayor Michael Bloomberg said.
"If you see something that looks strange, just pick up the phone and say something but at the same time we refuse to let cowardly acts of violence to keep us from living in this city, a city that we love," he said.
More officers are patrolling landmark locations in the city such as the Empire State Building and World Trade Center site.