Amid mounting criticism of its crackdown on mail-order medications, U.S. Customs has released hundreds of seized packages to consumers since Friday, said Canadian pharmacies and U.S. lawmakers on Tuesday.

The crackdown began in November, when U.S. Customs and Border Protection quietly increased seizures of prescription drugs mailed from abroad.

The seizures – up to 5 percent of orders from American consumers, according to some Canadian pharmacies – sent thousands of mail-order buyers, most of them seniors living on fixed incomes, scrambling to obtain medications to control cholesterol, high blood pressure, diabetes and other conditions.

Then, without notice, postal carriers began delivering hundreds of packages – some held up for two months – to buyers from Florida to California.

Customs spokeswoman Lynn Hollinger said on Tuesday that she was unaware that withheld packages had been sent on to customers, and could not explain the reports from pharmacists and consumers.

Sen. Olympia Snowe, R-Maine, has joined in criticizing the crackdown, along with nine House Republicans, independent Rep. Bernard Sanders of Vermont and one Democrat, Rahm Emanuel of Illinois.

More than 30 customers called Winnipeg-based CanAmerica Global, reporting that they had received medications Tuesday that had been shipped in early January. At the same time, they received the free replacements the pharmacy had sent a month later.