MedStar Health has reportedly been hit with a virus that has forced it to shut down significant parts of its IT operation.

“Early this morning, MedStar Health's IT system was affected by a virus that prevents certain users from logging-in to our system,” explained the company, in a post on its Facebook page. “MedStar acted quickly with a decision to take down all system interfaces to prevent the virus from spreading throughout the organization. We are working with our IT and Cyber-security partners to fully assess and address the situation.”

“Currently, all of our clinical facilities remain open and functioning. We have no evidence that information has been compromised,” it added. “The organization has moved to back-up systems paper transactions where necessary."

Related: Hospital pays nearly $17G in bitcoins to hackers who disabled computer network

The health group, which runs 10 hospitals, the MedStar Health Research Institute and the MedStar Medical Group, describes itself as the largest healthcare provider in the Maryland and Washington, D.C. region.

The FBI told FoxNews.com that it is aware of the incident. The Bureau is "looking into the nature and scope of the matter," it explained, in an emailed statement.

The Associated Press reports that the virus has affected Washington's Georgetown University Hospital and other medical offices in the region.

A law enforcement official says FBI is assessing whether the virus is so-called ransomware. The official spoke on condition of anonymity because this person was not authorized to publicly discuss details about the ongoing criminal investigation.

Hospitals have become a target for cybercriminals using ransomware, malicious software used to extort money. The software can encrypt files until a ‘ransom’ is paid in a difficult-to-trace digital currency, such as bitcoins.

The scale of the ransomware threat was highlighted last month when a Los Angeles hospital paid nearly $17,000 in bitcoins to hackers who disabled its computer network. Henderson, Kentucky-based Methodist Hospital suffered a ransomware attack in February.

Related: Iranian hackers indicted for attacks on US infrastructure

During 2013, the number of attacks each month rose from 100,000 in January to 600,000 in December, according to a 2014 report by Symantec, the maker of antivirus software.

A report from Intel Corp.'s McAfee Labs released in November said the number of ransomware attacks is expected to grow even more in 2016 because of increased sophistication in the software used to do it.

The company estimates that on average, 3 percent of users with infected machines pay a ransom. It's not clear how many of those users were individuals and how many companies. Some ransomware attacks go unreported because the victims don't want it publicized they were hacked.

The first fully functional ransomware targeting Apple’s Mac OS X operating system was identified by security specialist Palo Alto Networks earlier this month

The Associated Press contributed to this report.