When officials from the Transportation Security Administration go before Congress, it's usually because a committee has an issue with the agency's handling of aviation security.

But a House Homeland Security subcommittee had the opposite problem during a Wednesday hearing: Panel leaders said they were concerned that TSA has dedicated too much of its resources to the aviation sector at the expense of railways, buses and other surface transportation.

"Clearly, the threat to aviation is still present, but TSA cannot ignore the obvious trend of terrorist attacks on surface transportation assets worldwide," said Sheila Jackson Lee, D-Texas, chairwoman of the Transportation Security and Infrastructure Protection Subcommittee. "Our domestic transit, bus, and rail systems have thus far been spared, but terrorist attacks in Spain, Great Britain, India, and Russia over the last few years have emphasized how critical these systems are to protecting large urban areas."

While lawmakers noted that newly appointed agency head John S. Pistole has pledged to work on surface transportation security, they also emphasized that the topic is one that should have been addressed long ago. Jackson Lee said 85 percent of the agency's resources have gone toward aviation, while just 1 percent was dedicated to surface transportation. Although airlines are a proven terrorist target, she called the disparity unbalanced.

Subcommittee ranking Republican Charlie Dent of Pennsylvania noted that, of the $8.2 billion total for TSA in President Obama's fiscal 2011 budget request, $6.5 billion would go toward aviation security and just $138 million to surface transportation. But cases such as that of Najibullah Zazi, an Afghan resident of the U.S. who pleaded guilty in February to plotting to bomb New York City subways, show that attacks on ground transportation are well within the realm of possibility, Dent said.

Complaints about TSA's work in the surface sector came from across the board. Carlton I. Mann, assistant inspector general at the Department of Homeland Secuirty, testified that in past reviews, his office has found that the agency's surface transportation security inspectors labored under unclear and unduly complicated chains of command and poorly defined mission priorities. Instead of doing actual surface training work, many of the inspectors were stuck performing mundane, non-specialized tasks like handing out plastic bags to travelers at airports, he said.