The FDA banned Medtronic (NYSE:MDT) from importing a pair of its catheter systems after an overseas facility failed to correct manufacturing issues cited in a February inspection, according to a recently unveiled FDA warning letter.

The federal watchdog agency banned Medtronic’s Amphirion Plus and Diver CE PTA Catheters, which are manufactured in a plant in Italy, after determining that the medical device giant hadn’t adequately mitigated "serious" violations of current good manufacturing practice requirements.

The inspection was conducted from Feb. 4 through Feb. 7, 2013, during which time investigators noted 7 primary concerns, including excessive microbial counts on some surfaces, failure to validate computer software, and various procedural issues affecting design changes, calibration and FDA reporting.

"Given the serious nature of the violations of the Act, the Amphirion Plus PTA Catheters and the Diver CE PTA Catheters manufactured by your firm are subject to refusal of admission," according to the letter, dated May 6, 2013. "As a result, FDA is taking steps to refuse entry of these devices into the United States, known as “detention without physical examination,” until these violations are corrected."

In order to lift the ban, Medtronic must submit a written response that satisfies the agency’s concerns, and they FDA may conduct another inspection in order to "verify that the appropriate corrections and/or corrective actions have been made."

That’s more bad news for Medtronic, which is also at the center of a probe by the U.S. Attorney’s office for Minnesota, which wants a closer look at the medical device company’s compliance with the Trade Agreements Act.