U.S. Transit Systems on Code Orange

The Washington Nationals halted their afternoon game against the New York Mets at RFK Stadium to offer a moment of silence for the victims of the attacks. The sellout crowd rose to its feet, and players stood in the field, caps over their hearts.

Outside the British Embassy on Massachusetts Avenue NW, visitors brought flowers, offered prayers and lined up to sign a condolence book. One man held a placard that read, "Today, we are all British," Reuters reported.

Morning commuters on Washington's transportation network were greeted by the increased police presence and sporadic reports of suspicious packages, which briefly disrupted traffic and transit operations.

Metro officials closed the Medical Center station on the Red Line for about an hour Thursday morning after a "suspicious package was found in a station bathroom," according to Metro spokeswoman Candace Smith. Pete Piringer, a spokesman for Montgomery County Fire and Rescue, said the package was later determined to be "a box of electrical components found in an employee bathroom."

An Orange Line train was held at Metro Center for a security check while an officer wearing black combat boots and a camouflage green jumpsuit walked slowly from car to car, his eyes scanning crevices while his hand rested on the trigger of his gun.

"It's necessary," said commuter Jim Roby of Waldorf after the armed officer passed him. "We're a target just like London."

U.S. Capitol Police shut down the traffic circle in front of Union Station after two U.S. Park Service employees reported seeing a battered brown suitcase abandoned at a Metrobus stop.

Four police vehicles swooped onto the scene, red, white and blue lights flashing, to redirect traffic away from the Metrobus stop while the suitcase was examined by officers from the department's hazardous materials unit.

The suitcase was deemed harmless and the circle later reopened.

"Whenever we have events like this, when people leave stuff laying around, passengers tend to become more vigilant and call us about it," said Montgomery County Fire and Rescue spokesman Piringer.

Metro spokesman Lisa Farbstein said Metro restrooms will be closed today and that sweeps of rail yards and bus garages are being conducted. Farbstein told commuters to be on the look-out for any suspicious packages or activities.

Metro Transit Police Chief Polly Hanson said Metro will deploy three-officer "sweep teams" on Metrobuses and trains throughout the day. One member of each team will have a bomb-sniffing dog, she said, while another will carry a "long gun" and the third will have his hands free. She said some cars and buses will be stopped and searched by dogs.