Police forces along the East Coast are teaming up to protect Amtrak (search) trains traveling between New York and Washington.

It's the latest in a series of security measures begun since last month's deadly London transit bombings.

Officials say they have no information about a specific threat against the route, which is the most heavily traveled in the Amtrak system. But a New York Police Department (search) spokesman says recent security reviews have raised concerns that a route involving "two high profile cities" might be a target.

The increased security — which starts today — involves police officers from New York, New Jersey, Maryland, Washington and other jurisdictions.

A spokesman says officers will be on the lookout for suspicious packages and activity on trains and tracks. The team effort also includes the use of police helicopters and bomb-sniffing dogs.