Jin Lee / AP
An Amtrak K-9 division police officer stands guard at Pennsylvania Station in New York on Sept. 9. The city is deploying additional resources and taking other security steps in response to a potential terror threat before the 10th anniversary of the Sept. 11 attacks.
Justin Lane / EPA
New York City police officers search the back of a man's vehicle at a checkpoint on Broadway in New York on Sept. 9.
NBC, msnbc.com and news services report:
Security has been enhanced around the country in the weeks leading up to the 10th anniversary of the Sept. 11 attacks, a date officials have long known could be an appealing time to attack.
The FBI and Homeland Security Department issued a joint intelligence bulletin Thursday night to law enforcement around the country urging them to maintain increased security and be on the lookout for suspicious activity. Read the full story.
New York and Washington are on high alert after United States intelligence officials received information about possible attacks leading up to the 10-year anniversary of the 9/11 attacks. NBC's Pete Williams reports.