Pentagon Bomb Scare: Suspect Arrested.

A man is in custody after police found ammonium nitrate, spent pistol shells, and al Qaeda statements in his car.

Alex Brandon / AP Photo

WASHINGTON—A suspicious man apprehended near Arlington Cemetery and a car with a suspicious backpack hidden behind bushes near the Pentagon spurred fears about a possible terror plot Friday morning and snarled rush-hour traffic heading into the nation's capital.

Law enforcement officials told The Daily Beast the backpack appeared to have some suspicious materials and police disrupted the device it in an abundance of caution as police tried to learn more about the situation. The man taken into custody after a foot chase was a U.S. resident in his 20s and nothing in an early background check indicated any ties to terrorism, a senior law enforcement official told The Daily Beast.

The official, who spoke only on condition of anonymity, saidthe man was spotted inside America's landmark military cemetery early Fridaymorning in the Washington suburb of Arlington when the cemetery was closed andhe fled on foot before being apprehended at a nearby military installationcalled Fort Myers.

The man's behavior raised enough suspicion that law enforcement officials were treating it as a possible terror plot until they figure out what happened, officials said. "There are signs to be concerned about with this, but it’s early,” a second law enforcement said. The man was not cooperative and had some materials with him that raised suspicions, officials said.

Afterthe man was taken into custody, police began a search for any suspiciousvehicles and found a red Nissan located in the bushes near the Pentagon's northparking in Arlington, the official said. Police spotted what looked to be asuspicious package, which turned out to be a backpack inside the car. A bombsquad was called in and decided to “disrupt” the package using water cannons,officials said.

TheFBI, U.S. Park Police, Arlington Police and the Pentagon force protectionpolice were jointly working the case. With major traffic arteries into the cityclosed by the scare, Washington commuters were trapped in long lines of stoppedtraffic on all the major thoroughfares, creating an unusual traffic jam in acity that often sees lighter traffic on summer Fridays as resident flee tonearby beaches.