Authorities have increased security in Washington, DC and New York City, as U.S. officials investigate a possible terrorist threat timed to coincide with the September 11 anniversary.
In Washington, armed guards are stationed at the Kennedy Center, where President Barack Obama and first lady Michelle Obama will attend a memorial concert Sunday evening. Earlier, officers prohibited tourists from gathering near the White House.
In New York, police set up checkpoints at bridges, tunnels and subway stations. Bomb-sniffing dogs were deployed across the city, while surveillance cameras scanned key areas, including Ground Zero, the site where the World Trade Center towers once stood.
The high level of security follows an intelligence report detailing a “credible but unconfirmed” threat of an al-Qaida plot to attack the United States during the anniversary. Authorities believe three individuals may have been tasked to carry out attacks using car bombs.
Speaking to Fox News Sunday, White House counterterrorism chief John Brennan said President Obama met with his national security team Saturday and Sunday and that they are staying on top of all information coming in related to the possible threat.
In a sign of the heightened caution surrounding the September 11 anniversary, authorities called in fighter jets to escort at least two passenger planes and closed down part of a Missouri airport after disturbances that were ultimately thought not to be linked to terrorism.
Authorities intercepted a flight from Los Angeles to New York City after flight attendants reported one or more passengers had locked themselves in a bathroom Sunday afternoon and were refusing to come out. A statement from the Transportation Safety Administration said the flight landed safely at its destination and the jets were called in as a precautionary measure. It said the plane was met on the ground by law enforcement officials who will interview the passengers.
Similarly, fighter jets escorted a flight from Denver to Detroit after being alerted to passengers behaving suspiciously. That flight also landed safely.
And part of the Kansas City, Missouri, airport was briefly evacuated and shut down on Sunday when a man refused to allow TSA agents to examine a suspicious object in his luggage. The item was deemed not to contain explosives, but authorities have detained the man while they continue to investigate.
Al-Qaida terrorists flew planes into the World Trade Center and the Pentagon, just outside Washington, on September 11, 2001. Another of the hijacked planes crashed in rural Pennsylvania, as passengers and crew fought the terrorists.