In an abrupt change, Homeland Security Secretary Michael Chertoff announced Thursday that all packages brought to airline counters to be shipped on passenger flights will now be physically screened.

Until yesterday's announcement, an individual could bring a package weighing less than 16 ounces to airline counters a half hour before departure, fill out a form, pay a fee and the package would be rushed onto the flight for speedy delivery, according to Congressman Ed Markey (D-MA).

While praising today's action as a good step forward, Markey accused the Bush Administration of "bending to corporate interests" by not enacting his proposal to require 100 percent screening of all packages placed in the cargo hold of passenger planes.

Andrew Howell, in charge of Homeland Security Issues for the U.S. Chamber of Commerce, told ABC News his group opposed 100 percent screening of packages because it would create a bottleneck in the delivery of express shipping of priority items.

In an interview taped last week for an ABC News Special 9/11 Anniversary Report, Rep. Markey said that "as a result of the lobbying of the cargo industry, of the airline industry, there is a wide open opportunity for al Qaeda to place an explosive onto a plane in the United States."