Americans import a "substantial and increasing" number of illegal prescription drugs, but efforts to stop the sales remain scattershot, according to a federal report released today.

The report by the Government Accountability Office echoes criticisms raised since 1999 by various regulators, law enforcement agencies and congressional committees.

The report comes as some state and local governments, including that of Montgomery County, are allowing their employees to import medications to reduce drug costs.

Millions of packages of medications, including addictive painkillers, are shipped into the United States from foreign sellers every year, yet reliable data are lacking despite years of debate about the risks of Internet drug sales, the report says.

Estimates given to Congress range from 2 million to 20 million packages a year.

The "very limited" information prevents regulators from directing resources efficiently to prevent shipments of addictive substances or other medications that could be harmful, the report says. Virtually all prescription drug purchases from foreign pharmacies are illegal because the sellers operate outside U.S. rules that regulate drug distribution, labeling and safety.

Last year, U.S. Customs and Border Protection organized a drug-imports task force consisting of representatives from several federal agencies.

Both the Food and Drug Administration and the Drug Enforcement Administration have streamlined some procedures to make it easier to intercept packages containing illegal prescriptions. Stopping such imports is a "complex undertaking" and the task force "appears to be a step in the right direction," but clearer priorities and benchmarks are needed, the report says.

The report was sought by Sen. Norm Coleman (R-Minn.), chairman of the Senate Permanent Subcommittee on Investigations, and Rep. John D. Dingell (Mich.), ranking Democrat on the House Energy and Commerce Committee. Though noting some improvements, Coleman said in a statement that "efforts to work cooperatively between the various agencies and to engage the private sector have been lacking," leaving the Internet "a virtual black market for controlled prescription drugs and bootleg pharmaceuticals."

Dingell said in his own statement that "while rogue websites continue to send their drugs into the U.S. with impunity, the agencies most responsible for stopping this chaos are completely out of ideas."