WASHINGTON (Reuters) - A Covidien Plc device for rare malformed blood vessels can get stuck in the brain and has been linked to nine patient deaths, U.S. regulators warned.

The device, made by Covidien unit ev3, uses a spongy material to block off blood flow to abnormal tangles of blood vessels before they are removed by surgery. The material is delivered to the brain through a tube inserted into a groin artery, known as a catheter.

But the catheter can get stuck in the spongy material while inside the brain, causing serious complications including hemorrhage and death, the U.S. Food and Drug Administration said in a notice posted to its website on Thursday.

Since the device was approved in 2005, the FDA said it has received more than 100 reports of the catheter breaking after it became stuck, including nine deaths. In at least 54 cases, the catheter could not be removed, leaving it implanted in the patient.

"Neither (the spongy material) nor the catheter is intended to be long-term implants, and patients may need additional medical interventions to have the catheter removed if it becomes entrapped," the FDA said in the notice.

If the catheter is not removed, parts of it can also migrate to other parts of the body.

The FDA said it changed the label for the device in April to let doctors know about the risk of the catheter getting stuck in people's brains.

Malformed vessels, called arteriovenous malformations, or AVMs, afflict about 0.5 percent of people and can lead to aneurysm and stroke when left untreated.

In New York Stock Exchange morning trading, Covidien shares were up 1.8 percent to $53.41.

(Reporting by Anna Yukhananov; Editing by Gerald E. McCormick)